Assign categories from Payees

Hi. I love the SW, just what I was looking for thanks, but an initial problem I haven't been able to find an answer for. I import a set of transactions from a QIF file; then go into Payees and assign some of them to categories. If I then run auto-assign, it doesn't categorise other transactions based on the Payees, but yet if I open a single transaction, it does correctly fill the category based on the Payees. I just want it to do that same action across all the transaction (assign category based on payee), but can't work out how to. A fresh import doesn't do it either. I know the SW can make the correct assignment per the individual transaction dialog, but how to get it to batch process? FYI, I know that if I go into Manage Assignments, and add a rule to set a category for payee, that does work when I auto process. But this is much more time consuming (creating a rule for each) compared to using the Payee dialog to assign the category (in list format). Help please (and thanks!). Nick.