I haven't done this for many years but was able to do it and successfully program a VW style switchblade key for my 07 GT.
When you are doing the on/off cycle are your doors closed?
When you hit it just right your doors should lock / unlock and I seem to remember you had to have the door closed.
I don't recall being limited to 10 seconds so it was just a fluid key in ignition and move to on then to off and so one for 8 times ending on ON and bingo.