What do you mean by "exactly the sp map turned in mp"? Usually the SP maps don't work for MP because they tend to be more linear (U2 is often criticized for that).
Even when the map has multi paths, the goal is often in a bottleneck and/or deadend. These are usually the defensive missions in Unreal 2 - Swamp, Kalydon, Sufferon, and Janus roof. Because of the nature of these missions, the maps in general are better suited for team games, with some modification to the deadend. However XMP is another story...
XMP adds to the complication with players having much more mobility than characters in Unreal 2 (and most games for that matter!). This means the paths, obstacles, and pits all need to be longer, wider, and taller. Not to mention support for other features of XMP (not in Unreal 2) such as vehicles and manned turrets.
Imagine the U2 tutorial deathmatch arena was "exactly turned" into an XMP map, it would be way too tight. And RGB would be considered wide open for U2.
A few XMP maps have used the theme of certain U2 maps, including some meshes, textures and particles. But the entire "floorplan" had to be made from scratch. Examples include Nakoja, Hell, Archeron, and Drakk.
These maps show how much different they have to be from the SP map they are inspired by. And it seems the more they are adapted to XMP, the more they are different from the SP map. Nakoja is very losely based on the SP map, and professionally designed. Yet it's still criticized for being less compatible with XMP gameplay (too small, too many gens, caps too fast, too hard to drive around, etc).
Having said all that, I do believe it is possible to make a very XMP-ish map using various structures and landscapes from U2, as many have tried. It just takes a lot of effort and skills, which I probably lack.
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