Excel 2007 : Problem when updating dispersion charts

hello there,

I have this word with a bunch of graphs and tables linked to an excel file
changing the file and updating works fine, but if I change the source of the link the dispersion graphs (only) do not update at all. The most bizarre thing is that when I select "edit data" from the contextual menu it actually opens the correct file and chart!

anyone had the same problem??

any workarounds??

at first I thought the problem was that I had added text boxes and things on the graph and that caused the problem, but now I'm trying with unmodified charts and the problem persists...

help!