Mail 2.0 - Composing in HTML / Rich Text



I have just been testing the integrity of Mail at sending HTML/Rich Text emails to Outlook with regard to the message's apprearance once it arrives.

After playing about for about an hour now I have found a few problems. It appears that the Rich Text in Mail 2.0 has changed from 1.0. My signatures from inported from the previous version of mail displayed correctly, in the correct font, size and colour. However, signatures I have created using Mail 2 do not keep their formatting when viewed in Outlook. This also goes for any parts of previous signatures I edit. They look fine in mail, but in Outlook they're not right.

Does anyone know how to sort this?