I imagine it's the same as American soap operas, only with better beer. Seriously, though, I have a friend who was a story supervisor for an American soap. Apparently they have such an incrediblly large mill of worker bees they need entire departments develoted to managing screenwriters, story developers, character developers, dialogue writers, producers, editors -- all focused on different aspects of what becomes the final story. There was a great BBC documentary on soap opera writers (I think it was based on the Eastenders staff), and there are several decent looking online resources, like: http://www.gather.com/viewArticle.action?articleId=281474977564641. The structure is very strict though, I thinjk that's the only way a network can keep any semblance of coherence on what eventually gets aired.

Ben, I'm not sure if a Belgian soap is going to be more like an English soap such as Eastenders or Coronation St, or more like an American soap such as General Hospital or Guiding Light. In any case, afaik, there are no specific screenwriting rules that separate soap opera over regular tv drama. Just remember, though, that soaps are highly serial, weave multiple story lines, and use a limited number of indoor sets (i.e they're shot *cheaply*). And also, they rely heavily on cliffhangers, so story lines get resolved across episodes, and not within a single episode. In the US, a soap opera writing team is cranks out 5 hourly episodes/week for something like 48 weeks/year (As The World Turns hit 13,858 episodes in 54 years). This is important, because that kind of production leaves little time for polishing a script (which is why soap opera is so tacky... they're basically shooting first drafts in one or two takes). In some cases, I've heard of writers leaving space for the actors to improvise their exact lines. Otherwise the rules are similar, imho, to regular serial TV drama: each commercial break defines the end of an act and the start of the next act, which define your dramatic beats. So you have to write with that structure in mind. How many commercial breaks depends on the broadcaster. Bear in mind that your characters will tend to be wealthy and highly promiscuous/incestuous, will often have identical evil/good twins/triplets/quads, and suffer from various forms of clinical amnesia. Here are some scripts for tv dramas, some of which are quite soapy: http://sites.google.com/site/tvwriting/us-drama/show-collections