Foaming agents for drywood termite treatments
 

Does anybody know if there are any foaming agents that have been
approved for use in California by either Do-It-Yourselfers or Pros
with termite treatments (e.g., Premise, Termidor, or Bora-Care)? I see
that epestsupply.com's Masterline Foam page says it is "not for sale
in California" and pestproducts.com's Termitafoam page says it "cannot
be shipped to AK, CA, NY." I haven't yet contacted local outfits.

If I fumigate or otherwise kill active infestations, will foaming or
spraying into wall voids protect the studs from -future- drywood
termite infestation? Does the foam or spray settle so that only the
support beams and the lower portion of the studs are protected? Is
foaming or spraying about as effective or nowhere near as effective as
a "protectant" than injecting studs and beams directly?

Thanks in advance to all,

Mike