[Elecraft] CW to RTTY/PSK encoder question

[Mike]

The final clincher on my ordering the K3 was the innovative CW to PSK/RTTY encoder 
for no computer data mode operating.
No one has mentioned how this function is working.
The manual says that you plug in a paddle into the radio and send CW and it will be 
echoed back with the tones and be sent  in your selected data mode.  
My question is if you can also feed CW into the radio via the KEY jack and do the
transformation from CW which will be generated from an external keyboard/keyer 
such as the Microham Microkeyer. 
I ask this now because it will probably be a while before Microham offers a DB37
cable set for the K3 and before I expend the time searching out a local source for
a DB37 serial plug/cable and make up my own interface I would like to know
if it will work with raw CW sent to the KEY jack or only with internal keyer generated code.
                              Mike WA8EBM