[RTTY] Interface question(s)

[Larry - K2GN]

Hello to all:
Been following this reflector for a while.  Lots of info.
I'm trying to get back into RTTY from years ago.
Last RTTY setup was with a Flesher TU-170 and a TRS-80!!!!
Had a model 15 in the loop too!
My setup is:
I have a Yaesu FT-1000MP Mark V interfaced to the sound card via an MFJ-1279.
Software is WriteLog, Mmtty/RttyRite.
I use this setup for CW and SBB.
Seems to work on AFSK, but I can't get the FSK to work.
The rig keys but only a single tone, no shifting.
The only thing for RTTY in the MFJ manual says that the CW Key out 
can be used for direc tkeying of the radio for CW or FSK.   My PTT 
keying is via the RS232 port.
I've paralleled the CW Output Keying to go to PIN 1 of the DIN Plug 
for RTTY on the FT1000.
Radio keys, single tone, no shift.

Questions:
1. What could I be missing?
2. Is FSK still the preferred method?
3. Any recommendations for different a infterface?

Thanks in advance,
de K2GN/Larry