Centering a mergefield under a signature line

[nfotx]

I have a list of documents to be signed by individuals. To make the documents (legal contracts) appear very professional I would like to center the signer's name under the signature line. Because the names have various lengths a simple tab won't work.

Is there a way to center the merge field for their name under a line of standard length?




________________________________
Very Long Name stretches out

________________________________
Short Name