[OSL | CCIE_Voice] Connect router with FXS to Proctorslab??

[CCIE OSL]

I have a simple question,
Say I want to connect my 1760 with FXS port to ProctorLabs Vrack.
Is there a way I can connect this router?

I have 3640 router providing VPN,
I just want to ride the VPN but connect instead of phones, 1760  router 
with FXS.
and test SIP or MGCP.

Anyone done this before?

Please let me know,,

Thanks...