Problems creating a compact database based on database first model / Nullable cousing errors

Question

I am using ef database first to create my entity classes. Now I would like to create a compact database from these entity classes but everytime I try to query the compact database (what should create the db becvause it does not exist so far) I get the following error message:

"There is no store type corresponding to the EDM-Type 'Edm.SByte(Nullable=True)' of PrimitiveType 'Sbyte'"

So far I could not find any way around this. Sadly I'm not able to change the db.

Hope you can help me solve this problem!

Thanks, B.O.S.