Handling of nill element is not consistent against different types

I am experiencing problems with nillable elements. The behaviour of Castor is not consistent between xs:string and xs:integer elements. While xs:string elements are defaulted to null, as expected, xs:integer defaults to 0 even if the element is declared as nillable and nill.

I haven't been able to track down the issue in the code, but I'm attaching a simple test case showing my issue there.