Auto-bill Payroll Deduction

We have a number of employees who make payments on a pledge through payroll deduction, and I'm looking to set this up as auto-billing. Right now, we just have to manually enter the exact same pledge payments on the exact same days twice a month, and it seems like the perfect auto-billing situation. Obviously it wouldn't actually run a charge like a credit card, but it would make it much easier and less menial to square up with finance.

Any advice?