How to use cell value after cell formating?

[Carlsbergen]

Hi.

I have used Format Cells -> Number -> Category: Custom
and inserted Type: 00

This makes it so that:

If "1" is entered into the cell, it will display "01"
If "12" is entered into the cell, it will display "12"


This is exactly what I want it to do but here is the thing:
It displays "01" but the cell value is still just "1"
I want to be able to use the cell value in another cell where I have typed in:

="AP" & E5

where E5 is the cell in question.

The problem is that in this case I will get AP1, but I want it to be AP01


Any ideas on how to solve this?

Btw, just using "AP0" in the formula wont work because then I will get
"AP012" for "12" and thats not right.


Any help on this is greatly appreciated.