Draw My Signature

I am creating a form that needs a signature field which will be signed by users with touch screens.  I would like to set it up so that when they click on the digital signature field it executes the Sign > Place Signature > Draw My Signature without them having to click on those options to the right.  Acrobat will not let me use the Draw my signature option when a Digital Signature field is in the document.  So is there a javascript that I could use on a digital signature field or on a button that would execute this?  Ideally, I would like for them to click Sign, it pop up the window for them to sign with their touchscreen and then click to accept the signature.  Once they accept, the drawn signature then appears on the line.