I don't know anything about Maximus, but with mame, there's the easy way, the semi-auto way, and the long way.
Short:
Enable mouse for all games: change "mouse 0" to "mouse 1" in mame's ini file. This enables mice for all games, whether they need it or not. Also, make sure Maximus isn't sending "-nomouse" to mame, as this would over ride the mame.ini setting.
Semi:
Enable mouse for dial & trackball games (& maybe stick games): change "dial keyboard" to "dial mouse", and "trackball keyboard" to "trackball mouse" in mame.ini file. This enables mice in all game that have a dial or trackball.
Long:
Make game specific ini files: make a new file containing only "mouse 1" and name it the rom name. So for Arkanoid - Revenge of DOH, that would be arknoid2.ini. Put it in the ini folder in the mame folder. Copy and name the file for each game you want mouse enabled.
Other notes:
Do not enable -multimouse unless you want to use 2 TBs at the same time, or are very very worried about the spinner messing up the TB and vice versa. If you enable this, you will have to remap, which is a pain.