Approximate a signature on a Smartform

I realize docusign integrates with K2/Smartforms, however I dont have access to the product at this time and I need to have some way of approximating or indicating approval on a SF that will, at the end of the process be converted into a PDF and sent to an outside email recipient. I also realize that every person that has the approval task only has access to that task through K2 process rights/roles etc. I just need a visual way to indicate it was "Signed" like a digital stamp or watermark or something. Anyone come up with anything like that other than using Docusign?

Thanks

Dave