Digital signature reason returned as a text field

[pcw99]

I need help with returning a digital signature "reasons for signing" to a text field after signature.

I know that the postSign javascript is where I need to do this but I am unsure of the syntax to get the signatureInfo in LiveCycle ES4. I would like to return the reason for signing as the signature field caption if possible. If not then a text field located next to the digital signature.