[Kenwood] TS-850sat Frequency extension 40m

[NIK READ]

Help Please.. If You have not heard, the UK has been given an extra 100kHz on 40m (7.100 - 7.200) from 31st October 2004.
 
I have a TS-850 and would like to TX on the extra part of this band. As it is a region 1 model it only tx's up to 7.100.  I know the mod to open up the TX between 0 and 30 MHz but only want the 7.100 - 7.200 opened.   Has anyone any idea how this can be achieved ??..  
 
  Many thanks for any guidance..
 
  Nik M5DND