Analysis Service: filter fact table ?

I have a big table with several types of transsactions: PO (Puchase Orders, SO,( Sales orders), INV (Invoices) ...
I want to create cubes with only one type of transactions (1 cube for PO,...)
Where and how can I filter the rows I want to use in my cube ?
Thankscreate view, and for fact table in AS point at the view.|||create view, and for fact table in AS point at the view.

Among Numeric and Float

among numeric and float data types, which one is more precise for numeric calculations?
can any body help
thanx in advance...probably Float, because you can set the scale and precision.
e.g. Float(10,5) will show 1234.00023 (five decimal places or as many as you need)