cisco ASA or Watchguard XTM 515 and NVG510 issue
I am setting up a small business network. They need to do a vpn tunnel to their main branch and another off site location. The main branch has a watchguard with a static IP and an internal LAN. I use a lot of VLANs on that main system. The one I'm setting up requires me to use U-Verse. Well I've tried several of the fixes and to no avail.
This U-Verse has 5 static IPs set, with the IP like xx.xx.xx.10 to xx.xx.xx.14 with xx.xx.xx.15 being the NVG510/Gateway.
The internal scheme for the Main system which I will be VPN tunneling to is 10.0.xx.xx, with a static IP. I can set the router to whatever works. So my question is or frustration, the Cisco router freezes when I try to change it's internal IP to 192.168.2.1 vs 192.168.1.1. Since the main router is 192.168.1.254/29 (plus the static IPs). What do I do to get this Cisco to work. If it doesn't work then will a Watchguard XTM to Watchguard XTM be easier to to tunnel between? If so I can do that as I have a few lying around.
The other site uses a Cisco as well. Both the Main site and the other site are using other ISPs. This site is UVerse that I am setting up for a client.
Any help or suggestions would be appreciated.
Also, I've read a bit but none of the typical soiutions are not working.