3DMagic,
Getting hold of the Segment editor and watching the video tutorials by Lee will answer those technical questions.
I dont use the segnment editor but make them by hand - but the videos in the SegEd download are well worth watching as its gives a user an in depth understanding of how segments and entities are composed or should be made and how they are recognised/regarded internally by the engine.
Its a really good grounding into understanding FPSC internal workings.
Everyone should watch the videos - Pity they are not available separately.
Should be mandatory to watch for all FPSC users and then everyone would know how it works.
And yes one way or another you can place anything anywhere you want inside FPSC.
"I am and forever will be your friend"