DX-1G is not capable of TTL as far as I know. The flash output is always the same....there is no way to change the intensity either automatically as TTL should or manually (except for the "soft flash" setting). As such, the strobe will always fire at that same intensity if you set it to TTL.
I would love to be proved wrong in this. TTL would be very welcome.
I went to the DPreview.com and read extensively on the ricoh forums. THe DX-1G is essentially a rebranded GX100. Even the hot shoe for an external flash has no TTL capabilities.