In theory , you should be able to do the following:
The fix I.P. from the provider goes to the router.
The A800 gets an internal I.P. address.
You forward all the ports used by the quintum to operate to the internal I.P. address of the quintum.
You should be able to to use the extra ports on the router for web browsing, etc.
In order to get all the ports used by the quintum, you may need help from Quintum ,unless have a goos copy of wich ports are used by the tenor and want to share .
Good luck!!! You will need it.