Some of my contacts from my address book are missing from the 'send to' recipient list.

I suspect the problem is occurring because you have not given your contact an email address. If a contact does not have an email address it will not appear in the Address Book. This is functionality of Outlook and there is no work around, you must ensure every contact has an email address.

To summaries, for a contact to be vissible:
- must have a phone number in the contact's Mobile field
- the contact must have a valid email address