Customer Signatures

Not sure if this is the right forum but we are interested in whether anyone has done any work around storing electronic signatures. We have a PDA-based mobile sales solution. We would like to be able to capture a signature on the PDA and transmit it back to Head Office/SAP/a.n.other with a link to the associated sales order. In the event of the customer disputing an element of the order we would then be able to retrieve the signature. This can be done on paper but with the volume of orders we deal with this could be very time-consuming. We also use CRM.