Inserting a Signature In Outlook

Came across a strange change when using Microsoft Word as my Outlook email editor the other day. I suddenly couldn't Insert a Signature - I went to Insert -> Signature when composing an email, but the option wasn't there! After a bit of messing around I realised you had to use the standard Outlook email editor to have this back... Seems a bit strange, but hey, that's how it is!