whmcs and promissory notes

I need to know if i take alternate payment types suchs as a money orders, if whmcs comes with or has the availabilty to store a draft of a promissory note that i could have the client sign (digitally or otherwise) and or if this promissory note could be available to the client via the order form or as an option somewhere in their whmcs login.

I wanted to see what was available out of the box with whmcs first then i will continue this conversation in the customize section.

Has anyone set up something like this and how much is custom work and how much is out of the whmcs box?

Thanks.