Boss VF-1 Effect Processor

Hi

I am a new VF-1 owner and will be using it with a (soon to arrive) 
FCB1010, and wondered if one of the more experienced users on here 
could offer some assistance.  I'm happy enough with the FCB side of 
things (thanks to the software!) but certain features of the VF-1 are 
a little confusing to me.  I've searched back through the archives 
and can't find answers to my questions so I was hoping someone would 
be able to help.

Unfortunately I cannot use the "On/Off" with a single (1-10) pedal 
functionality because I need one of the CC messages in the FCBs 
global setup for another processor I'm using.  I considered using two 
separate pedals for effect on and effect off, but instead of this 
method I was hoping to be able to program one of the expression 
pedals so that it can function as "Effect on/off" and also control 
the master level of the effect.

Basically I want to set up the expression pedal so that when 
it's "heel down", the effect will be off and then when I push the toe 
down and the value increases to maybe higher than 10, it turns the 
effect on and controls the effect level.  Then when I've finished 
with the effect and push the heel right down again I want it to turn 
the effect off.  

So my questions are: 

1) Can I assign "Effect on/off" and "Master Level" to the same CC 
number and control it as I have described with an expression pedal?

2) And if this would be ok, what assignments would I need to make?  

3) Is it also possible to add an additional assignment so that a 
value of 120 - 127 was also off so I could leave the effect off in 
both the toe up and toe down positions?

I'm not using any other assigns for anything else as I will only be 
using the VF1 for single individual effects, either harmony or delay, 
and so there will only ever be one effect programmed per patch with 
all the other sections disabled.

Any assistance that you could give would be greatly appreciated.

Many thanks
Mark