If you don't already have it you can find the manual in this list and download/print it.
http://www.futaba-rc.com/manuals/index.html
I remember discussing that transmitter with you now, very good one even if not one of the MOST modern. It will serve you well.

As for mixes on on a 4 ch RX, not really. Some may say to mix a little rudder to your ailerons but I'd rather you do that manually.

You can do dual aileron servos but that doesn't take mixing or another channel, just a Y-cable.