If you are a ham - the answer is - that you can probably turn off the AM filter and have the MARS cap removal done and can transmit with the Kenwood TS 590S - since it is manufactured to operate anywhere it can listen - with certain types of approval.
I can only imagine that the manufacturer is going to be over whelmed when the band is approved.

Right now the only thing I am hearing in the said band is digital communications - no phone... Please don't kill the messenger...
Up and until now, the manufacturer refuses to do the MARS cap modification without a copy of a MARS license.

If the transceiver is new, it voids the warranty if you do it yourself.

Mine is more then 1 year old, hence it really wouldn't matter.

It would need to be realigned to operate there - because it was not purposely designed to operate there.

The problem is - once you do the MARS cap modification, you have to be real careful of where you operate - because the transceiver will transmit anywhere it can listen - which is anything from .001 to 59.999 MHZ.....