prefetching and derived attributes - wrong SQL

Hi,

I have a FetchSpecification (built in code) that fetches "transactions". 
The entity TransactionRow has a derived attribute defined as 
price*quantity. To speed things up I have set the FetchSpecification to 
prefetch on the reference to "TransactionHead".

Fetching the TransactionRows works, but when (pre)fetching the 
TransactionHeads we get an exception caused by trying to query 
price*quantity on TransactionHead. EOF has generated incorrect SQL.

If I do not prefetch on the reference to TransactionHead or if don't 
qualify on price*quantity everything works fine. If I do both of those 
things I get incorrect SQL.

I qualify on many different attributes in both TransactionRow and 
TransactionHead. Everything works just fine except the combination with 
a derived attribute and prefetching.

/Anders