Of course neither are true and that was reiterated today by Sony who in an interview made it clear they are sticking with Android for now. However, they also are clearly leaving the door open for a future with Microsoft but they are evidently being conservative here, waiting to see if it takes off:
We've done a lot of work with Microsoft over the years. We’ve launched a number of 6.xx products, but we made a decision not to bring a product to market in the first wave. We absolutely maintain to keep an open mind towards Windows Phone 7. We continue to engage in a relationship with Microsoft, but we haven’t made any concrete announcement about when and how we would introduce Windows Phone 7 into the portfolio.
We shouldn’t limit ourselves to one opportunity, but we aren’t yet ready to make any specific announcement about products. At this moment in time, there is clearly a galvanizing within the industry around Android as a creditable alternative to what’s out there, and we think that’s a good thing.
We're actually fine with this decision and think it makes sense. Sure, in theory having SE on board with Windows Phone 7 would be a huge sign of support but on the other...it's Sony Ericsson, the company with grand ideas and poor execution of nearly every major smartphone it has released recently.