So this is a horrible hack but I believe the process to convert to geth can be achieved using AlethZero and the Ethereum ethkey utility. You can import the gnosis wallet into AlethZero, once there you can dump the private key using
ethkey inspectbare --show-me-the-secret insert wallet name here
and then with the private key I believe you can them import the unincrypted key over to geth.
Let me know if that works/fails for you.