Can anyone help ...

Is there a mod to change the steps on a Yeasu FT-290MKII to 5Kz on FM.
I am trying to duplex for the ISS and cannot get to xmit on 145.990
FM..
I have tried setting one of the memorys to SSB and changing to FM but
them receving on 145.800, as soon as it goes back to to XMIT its back
on SSB ...

i'm at a loss .... is the ISS out of reach for me using a FT-290MKII


help would be appreciated