Hi Rob - same problem in Maya XFCE. I have a possible solution which I will explore at a later date but the following has been my experience so far:
Firstly my hardware: Away from home (last 6 months) I use a tiny Asus netbook with the usual Celeron 1.66 GHz processor hooked up to Bigpond Mobile BB via a Sierra Ultra modem. It doesn't sound much but it's enough for my needs when travelling. I'm a Linux only user but can boot into Windows if I really need to which thankfully is almost never. Maya XFCE is without doubt the best general purpose distro currently available. They should dump Firefox and make Chromium the default browser though. I've been a Mint user/supporter since the very start and it's my OS of choice for writing, communicating, and keeping records. I keep a number of other 'buntu types on USB thumb drives for the odd day when my computing taste buds need a change. For consistency I stick to 'buntu type distros as my personal feeling is that they have set the level of the bar and the others are trying to keep up.
I'm getting there..... To date, all the 'buntu 12.04 variants I've tried need a manual Mobile BB startup. Prior to 12.04, going back maybe to 9.04, all the 'buntu variants I tried would auto-connect. Therefore something changed in 12.04 and the only item I can think of that significantly affected hardware recognition at boot time, was the kernel upgrade which came with this version. Maybe I'm on the wrong tack but I'll do some more digging when I get home to my desktop in November and I'll have more time.
I know all the above is of little help but at least you now know of someone else who has the same issue. I'll post a solution in due course if I can but hopefully someone else on this forum will get to it first. Best advice I can offer right now is "don't buy Facebook shares and never run with scissors!"