[mkgmap-dev] splitter coordinates

Moin, I want to use splitter (r109) for cutting a predifined tile that includes the prime meridian. How do I set the coordinates west from the prime meridian? I tried to set the minimum longitude to 355 degrees, but the resulting tile was empty. Must I use -5 degrees instead? And what about a tile including the equator or the 180 degrees longitude? Gruss Torsten