I'm trying in install HGEC body and I'm following the readme but I'm not getting what he's saying.
He says:

1. Copy archive to (install folder)\Oblivion\obmm\omod\
2. Start Oblivion Mod Manager.
3. Click the Create button.
4. Click the Add Archive button, find and select the archive, then click Yes.
5. Click the Create omod button, then click OK when it finishes.

So what archive? There's six different folders in the HGEC folder. http://img707.imageshack.us/img707/8163/84190485.jpg

The HGEC folder that contains all of those folders, it should be in a compressed format. Then it wil lask for Omod conversion data, click YES and it will enter all the info for you.

Oh you mean I'm not supposed to unrar it? Just leave the rar file as it is and let OMM do the rest?

Yes. The .rar is the archive you select to add with OBMM.

Yeah.

Add archive = compressed file

Add folder = Uncompressed

Yes just Click on the Add Archive and follow the promts

Cool, it worked. Thanks.