Great Idea, but I have a couple of suggestions for you that may help. Here they are:
1. You could create a Question that would show up under the "Additional Information" section in the Schedule form as a Free Text Question that reads, "Who is the Person Responsible for Payment? (If different from the Organization Contact)." This could be made required or optional and turned on in FSDirect, MySchoolBuilding, and CommunityUse if necessary, or just FSDirect alone. This would allow either the Requester or an internal user to put the information in a holding place that could be then copied over to the Invoice when it is created. Default values can even be placed in the box, such as Name:, Phone:, Email:, Address:, etc.
The second part to this is that you can then copy the contact information for the person responsible for payment into the new invoice when it is created. All of the information you need is captured on the Schedule. I hope that helps with what you are trying to accomplish in FSDirect. If you have any questions or need more information about Questions in FSDirect please do not hesitate to contact the SchoolDude Client Service Team at (877)883-8337 or email@example.com and we will be happy to help you Denise. Have a great day!