There is no "original handset" hack for any Panasonic machine (apart from the L10), you need to have the machine either chipped or flash upgraded (the latter is preferable).
I understand this unit (or is it the RA91 I can`t remember), is an import version of the RA71 with Progressive Scan, pretty sure it`s not PAL-capable - so pointless to upgrade it anyway.
Steve
mailuk.com