[RTTY] Can I use RTTY TPF on Low tones?

[jflanders2@home.com (Jerry Flanders)]

I just discovered that after setting up low tones (1275 mark) for RTTY on 
my new ICOM 756PRO, activating the RTTY filter button (on left side of 
display) or using the internal RTTY decoder completely cancels my low-tones 
setup and restores 2125 as the default.

Is it possible to use low tones with either of the "RTTY Filter" or decoder 
functions?

Jerry W4UK