eMMC CM7.2 + SD CM9 = boot selection, HOW?

[iakovl]

right now i use the CM7.2 ]on my NC, works great... and as the saying goes... if it works, don't touch it

i need to do a repartition right now for the nook so i can go 1/5 (or 2/4) instead of 5/1 on the memory
i want to keep the CM7 becouse it works great for me so far
but i also want to try the CM9, going to get a bigger SD in few hours

so i'd like to know how to open a boot select menu between the CM7 and CM9 (also... the recovery would be a nice touch)

 

[patruns]

Put CM9 on a card and hold the N key down when booting to select eMMC or card....

 

[iakovl]

holding... nothing happens