This is enabled by a feature called Physical Address Extension (PAE), there is a kernel version in Ubuntu 32-bit that supports PAE, there is a meta package that does this for you, i.e. grabs the latest kernel version and allows future updates, just run:

“sudo apt-get install linux-generic-pae linux-headers-generic-pae”

Then restart your machine, Enjoy 🙂

Update: I’ve just restarted my computer, and it recognized my RAM, everything seems to be running fine till now, will keep you updated.