How to Pass Payment Method to API

[surfraz_urs]

Hi All ,
I am using this API "AR_CM_APPLICATION_PUB.ACTIVITY_APPLICATION" for Applying a Credit memo against a Refund Activity.
Can anybody please tell me how to Pass Payment Method to API - AR_CM_APPLICATION_PUB.ACTIVITY_APPLICATION.
I can see one Prameter caled "p_attribute_rec" which is of record type. I know that we need to pass Payment Method in some Attribute Value of this Record Type variable.but which Attribute it is ?????