AFAIK, unless both ITSP Provisioning and OBiTalk Provisioning are set to Disabled, the device should pull a config from the OBiTalk server shortly after each reboot. If that is not happening, there may be a problem at OBiTalk. Conceivably, if you are trying to set an invalid value, the device may not pick it up. I don't use the OBiTalk portal myself and know very little about it.
If you want to manage your devices directly, you can set both provisioning settings to Disabled, reboot the device and then make changes in its web interface. AFAIK, there is no way to export those changes back to the OBiTalk portal, so switching back would require you to re-enter on the portal, whatever you had changed in the device.
Assuming that the remote device is behind a NAT, you will need to forward a TCP port in the router to the private IP address of the OBi. Use a strong password (certainly, don't leave it at 'admin'). Also, choose an obscure port number. If the router permits, forward the obscure external port to internal port 80. If not, forward the obscure external port and, on the OBi, change Web Server -> Port to match. If the remote site does not have a static public IP address, you'll need to set up dynamic DNS on the router (or some other device running there), or have some external means of determining what IP address to access (for example, a provider to which it registers may show the public IP on their portal).
