Maximum print size in Excel

We have an HP DesignJet 5500ps and need to plot an Excel worksheet to it.
We'd like the plot to 150 inches wide. The plotter has roll paper. When we
print, the sheet cuts at the correct length, but the printed image stops a
little less than half way through, just blank paper. This doesn't happen in
any other application. I read at a university site I Googled that PowerPoint
has a maximum print size of 35" x 55" and was curious if this was true of
Excel. The only other issue it might be is lack of memory, but it doesn't
exhibit this behavior in any other situation and we print very large Project,
Visio, Photoshop and even web browsers. Thanks.