Wait a minute! Is your Spektrim kit the full telemetry kit? IF so, the Telemtry kit DOES NOT work on magnets!!!! I am initially wrong in my first post so ignore all that unless you bought the RPM kit that uses magnets.
If you have teh fulle telemetry kit, no magnets at all, the RPM sensor reads a reflective pieces of tape, so you have to put that little piece of tape on the flywheel such that it will cross under the RPM sensor.
In either case, you will have to do some creative fabricating to mount the Spektrum sensor part in the flywheel shroud so that it can ither read the magnet or the reflective sticker.
http://www.spektrumrc.com/ProdInfo/F...try_manual.pdf