How would you permanently mount it? How would you plug it into your amp?
Personally I think it would not be a good idea, for several reasons. Consider this, if you mount it INSIDE the guitar, then I would expect that would really increase the space between the pick up and the strings. This would surely reduce the effectiveness and performance of the pickup.
I would say if you REALLY want the CORD to be inside the guitar, I suppose you could install an end pin jack and connect it to that while still using the grooves to mount it.
You could, instead, consider using one of the many alternatives to a soundhole pickup, which would likely also provide superior performance over a soundhole pickup.