Dear All:
in the project module i create a new project with an invoice type progress invoice and the linked invoicing method to business partner also progress invoice as the help said exactly but when i'm trying to transfer the progress installment to central invoicing it gives an error report " progress invoices not present for project/customer ................ installment line 1"

can anyone help me solving this problem ??

thanks in advance

1. your BP code, invoice-to , invoice method must be progress invoice.
2. link your project with a your BP.
3. define your progress
4. than only you should generate your progress installment