thats how they have to be wired. usually people go under / behind the glovebox because there is less wire interference there. drop it down by where the floor speakers are, and under the door sill all the way back to the rear seat, then lift that out and put it through where the arm rest is.
there are some DIY's floating around the site. a search could prove useful.
<img src='http://www.bmw-forums.com/forum/uploads/post-46-1095116979.jpg' border='0' alt='user posted image' />
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