Oruxmaps Desktop to support GeoPDF ?

Hi,
maybe you know, that USGS maps for the USA with scaling 1:24k/1:25k can be downloaded from USGS Store for free.
This maps cover many interesting hiking areas.
http://www.usgs.gov/
However, the format is GeoPDF.
I tried to use MAPC2MAPC to convert a GeoPDF into some of the formats Oruxmaps Desktop can process,
but without success. (I've got some errors and did not know, how to deal with them).
Anyway i think, it would be very interesting to "open" USGS maps for Oruxmaps by providing at least some
working instructions (which tool, use setting x,y and so on) in order to use the maps in OM.

If you need some examples, i could provide them.

Thanks Robert