REFX - customize installment in lease-out contract

Dear gurus,

I would like to customize installments for certain contracts in REFX, lease-out, and I just can't.

I see in the flow type customizing thta we can assign reference flow types with relation - 310 installment payment. I added a line 'reference 310, from flow type 1000 to flow type 1008'.

In ssignment of account symbol to flow type I customized flow type 1008 with debit and credit on customer.

in define doc type I added a line REPP (periodic posting) / REIS (installment) / 1008 / D5 (doc type).

Now, how does SAP treat this information when I post with RERAPP? What is this supposed to generate? How are amounts installed (split by periods)?

Thank for you help.

Benoit Fanna