Movie clip position in a Scrollpane

I made a photo-visor in the next url: http://www.microscience.com.pe/hb/information/campus.htm

Well I need to put more text and using this photo-visor. I decided to use the scrollpane. I don’t have any problem to put the text and the photo-visor in the scrollpane.

But I have a problem. The width size of the photo-visor is very large, so when I load the movie clip, I need to move the vertical scroll to the center to see the photo-visor and the text. I use a mask in the photo-visor, but the problem continues.

I think that the best solution is to set default the vertical scroll in the center, I mean when I load the movie, the verticar scroll will be centered, but I don’t know how to made it.

Please help me or give me another solution.

PD: Check my problem in the prueba.zip file:)