Rotated Orthographic View?

[H Z]

I have a US lower 48 state/county map view in ESRI ArcMap that I have
exported shapefiles out of, and use them in MapServer/PerlMapScript to
generate maps for the Web.  When using a Mercator projection, everything
works fine, but now I need to use an orthographic projection.  When using
ortho in ArcMap, the map appears rotated, but I can use ArcMap's Rotate Data
Frame tool to get it in the right position.  Exporting the rotated map to a
shapefile and processing it in MapServer/PerlMapScript however doesn't
maintain the corrected rotation.

How can I have MapServer/PerlMapScript rotate the map prior to generating an
image from it?

Thanks!