I think this is incorrect in a number of ways:
* The Swedish High Court held specifically that Assange cannot be charged at this stage of the process; under Swedish law, with a domestic arrest warrant issued, he must first be arrested and face his prosecutor.
* The Swedish High Court specifically considered the videoconference option, which is not required under the ECHR, and, at the level of the High Court and consistant with the demands of the prosecution, rejected it: he needs to be questioned in person, and, depending on his responses to questioning, the Swedish may need to employ physical forensic science (as they would in any rape case).
* Swedish law requires the Prosecutor General to evaluate extradition requests on a case-by-case basis; under Swedish law, the government cannot offer Assange a blanket protection from extradition to the US. Incidentally, if this type of promise is common, I'd point out that the examples of it seem to have eluded the press; can you provide any yourself?
Most of these issues are helpfully excerpted by the author of this particular column from the Swedish High Court opinion upholding the EAW. You don't even have to search for it, or read the whole opinion.