Digital signatures on DD Form 1351-2 are NOT accepted. DTS includes an order/authorization module. Instead of authorizing digital signatures on the old forms, you should use DTS where ever possible.
Digitally signed orders are considered to be electronically signed orders. Typically, Adobe 9 or PureEdge software is used to create orders, but neither provides acceptable authenticated signatures. Also, letter orders that show "digitally signed" in the order issuing block do not comply with the regulation.
Digitally signed orders will be accepted if they comply with AR 600-8-105, or if the order/voucher is accompanied by an exception from HQDA Army G-1. If the order does not meet those provisions, DFAS must return the order for proper authentication.
HQDA Army G-1 is updating the regulation to include digitally signed orders. Until the regulation is updated or your command obtains an exception, DFAS must follow the current Army regulation.
Refer to Army Regulation (AR) 600-8-105, Chapter 2, paragraph 2-18 on this topic.