PS Payables Payment Interface

We're hoping to utilize the PS Payables Payment Interface to create payment records from a 3 party system.  We'd like to use the Pay Cycle as a "check writer" for a line of our business that requires specialized software to manage the transactions that make up the payments.  We'd prefer not to maintain vendors or vouchers for this purpose, but would certainly like to utilize our PS bank accounts and banking integration to process these payments.  However, I can find little uselful information on how the process works, and how best to configure for this scenario.  Any help is greatly appreciated.