Git buildId fails when Maven is invoked from another process (e.g NetBeans or packaging scripts)

Git is present on the path and standard 'mvn buildnumber:create" works, but invoking the goal from within IDE/Makefile/RPM scripts fails with:

[DEBUG] Configuring mojo 'org.codehaus.mojo:buildnumber-maven-plugin:1.0:create' -->
[DEBUG] (s) buildNumberPropertiesFileLocation = /home/jakub/rpmbuild/BUILD/masterkey-torus2-2.9/buildNumber.properties
[DEBUG] (f) buildNumberPropertyName = buildNumber
[DEBUG] (s) doCheck = false
[DEBUG] (s) doUpdate = false
[DEBUG] (f) getRevisionOnlyOnce = false
[DEBUG] (f) project = MavenProject: com.indexdata:torus:2.10-SNAPSHOT @ /home/jakub/rpmbuild/BUILD/masterkey-torus2-2.9/pom.xml
[DEBUG] (f) reactorProjects = [MavenProject: com.indexdata:torus:2.10-SNAPSHOT @ /home/jakub/rpmbuild/BUILD/masterkey-torus2-2.9/pom.xml]
[DEBUG] (f) readUrlScm = scm:git:ssh://git.indexdata.com:222/home/git/private/torus
[DEBUG] (f) scmBranchPropertyName = scmBranch
[DEBUG] (s) scmDirectory = /home/jakub/rpmbuild/BUILD/masterkey-torus2-2.9
[DEBUG] (f) session = org.apache.maven.execution.MavenSession@5893bca2
[DEBUG] (f) timestampPropertyName = timestamp
[DEBUG] (f) useLastCommittedRevision = false
[DEBUG] – end configuration –
[INFO] [buildnumber:create

]
[INFO] Checking for local modifications: skipped.
[INFO] Updating project files from SCM: skipped.
[INFO] Executing: /bin/sh -c cd /home/jakub/rpmbuild/BUILD/masterkey-torus2-2.9 && git show
[INFO] Working directory: /home/jakub/rpmbuild/BUILD/masterkey-torus2-2.9
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Cannot get the revision information from the scm repository :
Exception while executing SCM command.

[INFO] ------------------------------------------------------------------------
[DEBUG] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: Cannot get the revision information from the scm repository :
Exception while executing SCM command.
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:719)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalWithLifecycle(DefaultLifecycleExecutor.java:556)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:535)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:387)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:348)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:180)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:328)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:138)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:362)
at org.apache.maven.cli.compat.CompatibleMain.main(CompatibleMain.java:60)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Caused by: org.apache.maven.plugin.MojoExecutionException: Cannot get the revision information from the scm repository :
Exception while executing SCM command.
at org.codehaus.mojo.build.CreateMojo.getRevision(CreateMojo.java:727)
at org.codehaus.mojo.build.CreateMojo.execute(CreateMojo.java:443)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:490)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:694)
... 17 more
Caused by: org.apache.maven.scm.ScmException: Exception while executing SCM command.
at org.apache.maven.scm.command.AbstractCommand.execute(AbstractCommand.java:63)
at org.apache.maven.scm.provider.git.AbstractGitScmProvider.executeCommand(AbstractGitScmProvider.java:290)
at org.apache.maven.scm.provider.git.AbstractGitScmProvider.info(AbstractGitScmProvider.java:311)
at org.codehaus.mojo.build.CreateMojo.info(CreateMojo.java:747)
at org.codehaus.mojo.build.CreateMojo.getRevision(CreateMojo.java:694)
... 20 more
Caused by: java.lang.UnsupportedOperationException
at org.apache.maven.scm.provider.git.gitexe.command.info.GitInfoCommand.executeCommand(GitInfoCommand.java:56)
at org.apache.maven.scm.command.AbstractCommand.execute(AbstractCommand.java:59)
... 24 more
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2 seconds
[INFO] Finished at: Wed Mar 14 09:37:35 UTC 2012
[INFO] Final Memory: 19M/176M
[INFO] ------------------------------------------------------------------------