Access Connections Idle Timers?

[readysteadywhoa]

We've got a number of Thinkpad laptops which we're planning to outfit with Gobi 3000 Mobile Broadband adapters (including this x220). We would like the Access Connections profile to disconnect after xx minutes of inactivity (to prevent the user from leaving it on all night) but I don't see the option anywhere.

Is there a registry option or anything at all we can use via Access Connections? There's also the option to let an external dialer take care of the connection, but I don't know of a generic one (or something from Gobi/Sierra Wireless) that would work. Any recommendations?

Thanks!