System apps behave differently when they are compiled with Eclipse and when they are compied as part of the AOSP

[Android007]

Hi,
I don't understand why, but when I compile my app as part of the AOSP (in /packages/apps ) and run it on the compiled emulator, it uses the mdpi folders when searching for resources - and it makes no difference whether the emulator has its density at 320.

However when I compile it  with Eclipse, I get the right behaviour (resources are taken on the same emulator from the xhdpi folder).

What causes this behaviour?

Thanks