Not at all impossible - that’s exactly what Open-AT is there for!
The process is the same as for any other project on any other platform:
Read the documentation for the Digital Meter to determine its protocol(s) and interface requirements;
Read the documentation for the Fastrack to determine its capabilities and features.
Armed with that information, you can design your system to use the capabilities and features of the Fasatrack to meet the requirements of the Digital Meter.
As you haven’t given any details at all of the Digital Meter, it’s impossible to be any more specific.
Unfortunately, Wavecom now consider the M1306B to be obsolete - so there is precious little information available on the Wavecom website.
See: viewtopic.php?f=3&t=2160
Therefore you will have to speak to your local distributor, or get googling to see what you can find elsewhere…
Or, as you’re starting a new project, don’t start with an obsolete product - use a Fastrack Supreme instead: