VPN client software for Watchguard 700

I am supporting a customer that has a Watchguard 700 III firewall. Years ago, before I began supporting them, they purchased a 5 user MUVPN license. However, we cannot locate the actual client software to install on the user stations to utilize the vpn. I contacted Watchguard support and they no longer have the software available for download. They suggested searching the web for it. Does anyone have any ideas how I could locate this software? If someone has it they can contact me directly at my email address, khelt@isgtech.com, and I can send them a copy of the Watchguard license so you will know it isn’t for illegal use. (: Thanks for any help you can give me.

Kevin