I think if I read the post correctly you have the foot paddle that controls the AC on/off to the controller, a switch that controls the direction of the motor and the variable resistor hooked up as in that diagram to control that speed ? Not sure if that is a great setup...
I could be completely wrong on this...
So you wanted to be able to turn AC to the controller on/off with a regular AC toggle type switch... and the foot paddle to control the on/off of the motor, a separate SPDT center off toggle switch to control the direction, and a variable resistor pot to control the speed?
-->This is easy just rearrange your current components and add an on/off switch for ac...
This one is easy and can utilize what you current have I think...
1) Just take off your current AC paddle that turns off the AC power to the controller, add a regular switch... any switch... that fits the power requirement of cause, it shouldn't draw that much amp as long as it is AC rated.
2) take a look at the diagram on post #4 or your controller's manual. hook up would be the same, except that at the center pin of that reverse switch and the end that is to the variable resistor... you break the contact and add that foot paddle...
Or are you looking for ?
change the current AC on/off with a switch.
add a food paddle that can have variable speed with a separate SPDT center off for direction?
--> this you'll needed to hunt for that special paddle with a variable resistor build in... they do exist.... I know my welding machine uses it.. Not too sure where you would source the component of that...essentially this one is the variable resistor and build into the foot paddle I think... with an extra on/off that is build into the paddle... so you'll still needed that SPDT center off switch for dir control.
or
change the current AC on/off with a switch
have a foot paddle that can do reverse / forward (one of those double paddle setups)
and have a variable resistor some where to control the speed.... these type of foot paddles I have seen but pretty expensive I think....