You're not going to get it working directly (since you won't be able to 'source' scripts that aren't 'local', but why not pass the result through standard output. For example, call you ssh line like:
result=`ssh root@$mss_server "/root/robe....`
and have the last bit of your 'called' script print out the current value of the fmfm_never_configured_count variable.
Would that work in your situation?