Have got exactly the same problem and I'm also not happy about it. I was pretty sure that I had HTML Hotmail via exchange before.
I have reported to Vodafone and they have confirmed the problem and there engineers are looking into it.... dont know how much they can do.
I hve tried deleting and re-adding the account with no luck. HTML does work with POP3 but this is of no use to me and I want all my email accounts in one place so dont want to use the hotmail app.
Be pleased to here any news that you may have.