Hi Mac,
I am not sure I fully understand your requirements, but if I did, then I am not sure that multiple forms are the right solution, anyway a digital signature cannot move from one form to another, as it misses the integrity idea of digital signatures.
As Adobe uses versions technology to allow you to change a document and still keep its digital signatures valid, you can simply add a signature field after the manager has signed and allow the director sign on the new created field, this workflow will not invalidate the manager signature. If you right click a digital signature you can see the data (or version) that was signed by this signature.
BTW, can you please tell me what certificates are you going to use, and where are you going to store the signers private keys?
Thanks
Tal,
Tal@arx.com