why dont you just ask your enterprise administrator to create a private exception for the port you require?
If you can access it remotely via your home PC, and have an active VPN connection to your home PC from the office PC, route all traffic through the VPN and connect to it that way. This is ofcoure if the network firewall instant blocking outbound VPN tunneling again!
I guess at the end of the day, if they dont want you accessing this DVR, you wont have much luck!! They have alot more control then you lol...