Error - Material cost estimate with quantity structure

Hello Gurus!

Can anyone please help with the following problem:

I’m trying to do the material cost estimate with quantity structure, but the system is throwing back the message " There is no exchange rate for exchange rate type P on 1.01.2008: CHF -> EUR".

This happens because I have a subcontratation in my routing in CHF, and in transaction OB08, and I don’t had defined that rate (type P CHF –EUR).

I need to know if there is any solution to the system assumes other Type of Exchange Rate (the last real exchange rate that I have introduced in my system, not the planned!)

Points will be assigned to the suitable answer.

Thanks in advance.

Mary Jane