Hi mate,
To be honest, im not entirely sure. I used to have a free microsoft website that i designed myself, but i moved to a wordpress website, and i just host it with them. Basically wordpress is a design tool, so i design my site through wordpress not the host. I actually got a guy to redesign my site with wordpress so im not sure how he went about it but i know if i want to change anything on my site, i log into wordpress NOT the host.
All my email addresses are run through the host though and you have whats called a c-panel with the host, like a control panel so maybe if you migrated your complete site over, you could control it with the c-panel.
Best bet would be to email vidahost, thats what i did with all my questions before i signed up, they got back to me in about 10 mins. VERY helpfull!
Cheers,
Matt