External cash desk posting with payment form reference

[canarendra]

Hello,

We are using external cash desk for posting customer collection. These collections are posted to customer account real time and open item is also getting cleared. We have one more requirement wherein when we receive payment it has to be posted with reference to payment form and should clear relevant line items only which are attached to payment form.

Currently we are using contract account document as exterenal cash desk reference and payment is posted successfully with clearing. But due to change in business process we want to post and clear collection with payment form, which is not happening. It is not allowing to post and if it is posted then it is not clearing the line items. 

Please suggest how to use payment form reference id for external cash desk posting and clearing.

Regards,

Narendra