The focale was 17mm, thus 34mm in 35mm world.
Yes this is wide, but as i said before, this is 180° so it won't print nicely anyway. The problem is the height of the walls, more than 10 meters, 33 feets. i was taking the shots with my back on the opposite wall.
Using Autopano pro, based on the autostitch algorythm make the stitching quite easy. The perspective and verticality control was a little more difficult to obtain, and i was obliged to scan thru the very good tutorial of this tool to understand how to correct my initial geometry.
I recommand to everyone to try this very nice tool (http://www.autopano.net/) . You can use it freely to generate your panorama as the only real limitation of the unregistered version is the unability to save the project, but not the resulting images.
There are plenty tutorial videos how to use it and you can control quite a lot from control point quality to tone matching thru projection mode and lens correction. You can generate PSD and HDR output in addition to JPEG or TIFF.

Of course, as this is a French software, it is probably expensive for the US as it is priced in Euro's.

But, of course, you need not to overexpose your photos as i did in this case:cryin: