For one reason the definition of rape in Sweden is rather interesting. There is no concept of consent rather the accusation is apparently based on the amount of violence. All a woman has to do is resist for there to be a rape case and prove so. The result is that generally it seems to be all the court needs to do is believe the woman. Hence you could have the case of there being what happens a lot in other countries, a boozy night out, consensual sex, followed by remorse the next day. However you can then charge the man with rape. It's this fuzzy line that usually throws out rape cases (In Australia at least, and this is not necessarily a good thing) where alcohol was shown to be involved.
I am not a lawyer, and not that familiar with Swedish law, but I would be Assange or his lawyer is, and is also aware that if the women are really working on behalf of some other agency there is a high likely hood of Swedish law working against him. If that's the case he is unlikely to get a fair hearing.
NB if someone more familiar with Swedish law could speak up about this that would be excellent. I would love some corrections about the above with supported documentation.
BTW as an Aussie I am horrified that our PM Julia Gillard condemned him without any proof, and even more furious over their lack of involvement to help an Australian national. Convicted Drug Traffickers seem to get more help from the Australian government then people only accused of a crime.