Huawei B612 bridge mode?

I know there are some hacks to get the B525 to run bridge mode but I've not found anything for the B612. I received my B612 yesterday so had a few hours to play with it and see what I could set up.

Annoyingly in my area the 4G isn't massively fast (30-40mb) but it seemed to work okay for everything I tried apart from port forwarding.

My issue is I've got the B612 as the modem feeding my Asus router which controls everything else.

I tried accessing a machine in my house via http://abc.abc.abc.abc:9090 to try and get the port forwarding to work. It didnt.

If I hit the IP address externally it takes em straight to the 612's admin page so I know it's getting traffic.

I tried setting the IP of the Asus router in the DMZ.
I tried telling it to forward the ports in question to the Asus router, again nothing.

I'm using the 3internet APN and it seems my IP likes to change quite frequently but at the moment it seems I'm missing a trick.

- I didnt actually try with the 525 when I had it to see if I could access some of my home network remotely, I really should have.

I've fixed my problem. My Asus 87U firewall was blocking the requests for some odd reason. Turned off the firewall on the router and job done.

I'm attempting to do the same thing - use another router, with the B612 only as modem. As I'm not super knowledgeable about port-forwarding, etc; would you mind writing up the steps you used to set up your system? Thanks!