Payment Status 35

[Guest_imported]

I have set up a Purchase Order with retention payment processing. I have entered an invoice and approved it to have a status of 30 - fully approved. This invoice should then be included in the next check run processing. However, it remains in the approval que with a status of "35" retention. We currently do not use the Contract Administration module. Does this module tie in to the retention status? What should the process have been? What steps am I missing to truely approve this invoice and move it to the payment processing que?

Any help would be apprieciated.