How to combine two albums in one ?

Hi, I bough a new mac and with it came the fastideous task of re-adding all the albums to iTunes once again.

Everything was going fine until I added a album which has 2 CDs 14 tracks in one CD and 5 more in a Bonus CD what happen when I added the CDs to the library was that iTunes made two different albums.

I tried changing the info, the name of album, the name of the artist even the release year everything was equal, yet iTunes didn't combine the two albums in one as it should.

After I selected both albums went to get info, options and in the Part of a compilation I selected Yes, which made the smaller album to disapear, the songs are in the library, but the album disappeared from the album library.

Any suggestion ?