Find and follow the iSync plugin edits / hacks for the Maxx.
I had a Maxx phone for about a week before I got my v9m. I had to add and modify this file (RAZRV6.phoneplugin) in my /Library/PhonePlugins to get DUN working on my Maxx. When I got the v9m, it just worked ... I believe b/c of my work to get the Maxx to work. Here is whats listed for my v9m:
Device Name: Motorola Phone
Device Address: xx-xx-xx-xx-xx-xx
Device Type: Phone
Device Services: A2DP Source, AVRCP Target, OBEX Push Transfer, OBEX File Transfer, Dial-Up Networking Gateway, Headset Voice Gateway, Handsfree Voice Gateway
Serial Port: Yes
HERE is where I got the plugin. I forget exactly how I got it to work. Give it a try maybe someone else can help out.