An extension cable and the battery goes into some pocket, a fanny pack or a backpack. I also fashioned a clip form an old iPod case and was able to clip the battery to my Camelbak or the waistband, although it was pulling my tights down. The battery is too heavy to be attached to a helmet.
Remove the plastic, round part from the light head, there is a threaded hole in there. So now take a strip of metal with a hole on each end, bend it creatively, bolt one part to the fender mount hole and attach the light head to the other end.
Sorry, I don't have a closeup and I no longer have it mounted like this, but I hope you'll get the idea:
Okay, given what you said, I'm wondering if a p-clamp could be used as that strip of metal banding.
Re: that base on the MS that you said to remove to gain access to the hole- totally noobish question, but if that base is removed, can it be put back on? It probably does, but I haven't seen one up close yet to be sure...
Weird, there was an image in my post, now it's gone
Yeah, that's just screwed on, nothing permanent, so you will be able to put it back on. P-clamp would work, but you'd still need another piece, so I think this is a more elegant solution. You just need to bend a metal piece and attach it to the fork.