Hi tom,
why are you not considering hosting your own wordpress blog on another server of with a hosting company? That way you can install seo plugins but also perhaps resolve some of these issues that seem to be created by software used by wordpress. If you install it on your own server you get more of a hand in the possibilities of your blog. Still doesnt resolve the issues? Contact the wordpress forum for a technical assistant who perhaps can assist you.
At appears to me this is a very technical solution more appropriate at the wordpress forum but thats just me.
I would start by hosting it away from the wordpress server.
regards
Jarno