[Elecraft] Transmitting CW While in SSB

[Radio Amateur N5GE]

I've been doing the above with my first K3 #806 for a long time,
especially on 6m.  Today I was monitoring 2m USB on the other rig,
#1055, and heard a station calling CQ.  I quickly attached a paddle to
the rig and started answering the station, but no CW was transmitted
from the rig (still in USB).

I have searched the latest K3 manual using CW for the search criteria
and haven't found a way to turn the XMIT CW in SSB setting on.

What am I overlooking?

The firmware in the #1055 is 3.14.  The same as in #806.

Thanks,

Tom, N5GE
K3 #806, K3 #1055
XV144, XV432, KRC2
W1 and other small kits.
http://www.n5ge.com