So far, the word is as follows, just to clear up the FUD that's been spread around:

1) The Pearl works as a BT DUN device with Windows.
2) With some script jiggering, it does the same under Mac OS X.
3) With extensive tinkering, it doesn't work at all under any Linux flavor.

Either the Pearl is set to *not* work with specific BT stacks, or there's just something missing on the Linux side of the equation which needs to be fixed.

Poking around in the BT settings, or looking at the service books, doesn't really help here, since the Pearl provides a BT DUN profile to some devices, and not others.