I think I do have the bleeding thing. If you look at this picture it is in the bottom left corner below the brass filling tip. - I hope this is the thing you are refering to.
http://users.telenet.be/vanbeeumen/IMG_0425.JPG
I also have a second hand CO2 fireextuinghuiser heading my way, it was only 10 euro's. And as a start this should be more than enough to keep me going for a while.
http://users.telenet.be/vanbeeumen/IMG_0428.JPG
http://users.telenet.be/vanbeeumen/IMG_0429.JPG
BR
Marc