Default Samsung Galaxy Ace backup imei number

Hi,

I am going to change the ROM that is on my phone, I have done so previously and had no problems but thought it was time to change things up again

I was reading some instructions on how to install the ROM and it mentioned that I should backup my IMEI number. I have been trying to find a way to do this now for several days with no success.

The closest I have come to by using an app called "GalaxSim Unlock". It said it worked, although it only saved 1 file instead of the 3 that are meant to be there. All other apps just refuse to back it up.

Can someone point me in the direction of an app that will backup my IMEI or instructions on how to do it?

Thanks for any help.

Jay