nokia messaging doesn't require an @ovi mail address. Just register to use NM and then choose NM as your provider when setting up email on the N900 client. Once NM is set up you just add the @gmail account (NM can be set up to collect and display mail form multiple email accounts, but in your case just your gmail acct is all you'll need). I'm not clear whether you want replies from N900 to emails originally sent to your my@account.one to be sent from that account or from gmail - I think probably they'll come from gmail, suck it & see.