1. Derivation procedure is assigned to Business Partner in the Counterpary role. You can find it on "SI:Derived Flow" tab in BP master data (you can get there right from deal, or tr. TBI6 if i'm not wrong)
2. Yes, cash flow tab is based on 001 valuation area. This VA is very important. If you try to rename VAs other then 001, 002 etc and delete 001 - you'll get error. There is also note about that - you can't delete VA 001! So - use reports to get other postings.
If you want to have other data that isn't in deal master data and you don't want to use reports - use customer-specific tab pages in a deal (badi FTR_CUSTOMER_EXTENT, example FM FTR_CUSTOM_BADI_SAMPLE_START) and abap.