Cctv remote view/ adtran total access 900e

hey guys thanks for your help my question is?

I install cctv systems with remote viewing(this means a person is able to see his or her cctv cameras trough the internet with a software) I have done this many times in residential i get to access the router and open a port to let cctv access and I make it work, but know Im stuck -I got this project in a commercial location- I made my systems installation but I cant get it to remote view because the place owner haves a T1 system "where he gets internet and phone lines" let me put it like this-

T1 provider- verizo...."
TO
T1 model- adtran total access 900e
TO
linksys switch
TO
cctv dvr

my problem is that I do not know how to access this T1 to open a port for the cctv dvr

I tried to talk to talk to verizo..." but it looks like they don't know how to do this.

I read the adtran manual but I could not get an answer.

if you have any info about this please let me know thanks.