Sky epg data is OpenTv format and SiKinn is correct that its not been disassembled fully, so data format is not known. Mheg epg format for the Freesat channels is more known but secrets seem to remain with just a few groups that presently do not seem interested in dreambox development. That may change now that bbc/itv freesat are using Mheg.
Epg plugins for the dreambox tend to rely on rss internet based data for now.