I just went on the FAA registry site, and it looks like all or at
least most of the ASW-15 in the US are type certificated:

http://registry.faa.gov/aircraftinqu...W15&PageNo =1

If yours is among those, you should probably consult first with an A&P
or IA. If they are comfortable signing it off as a minor modification,
you're good to go. If not, they will probably be able to advise you
what hoops to jump through.

Thanks, Bob K.