It's incredibly difficult (I've heard impossible, but I DOUBT it's that) to weld aluminum to steel (or titanium, as might be the case with your 8t DRIVER (Note: drivers and cogs are not the same).

It won't work UNLESS you have a Profile cassette hub and one of the new Profile 1 piece drivers that are both RHD and LHD compatible. If that's the case, you can just flip two of the pawls to LHD while keeping two at RHD, and thereby "fixing" the 8t driver. Doing this will probably work for a time, but will almost definitely cause your engagement ring (LOLOLOLOL) to undo itself from the shell, unless it's a press fit engagement ring, in which case I have no idea what happens. Keep in mind that Profile hubs are spaced 110mm, not 120mm like your fixed hub is spaced, so you'll have to use washers on the inside of the dropouts accordingly.

Try it and tell us what happens?