Searching for multiple fields, and support for a new item not in the list?

My question is in two parts.

So, let's say I want to use the MultiSelect control as the "To:" field on an e-mail form, where you could select contacts from a list. The first question is, can you have it filter by both the label and value fields for a particular result? Say if the label is their name and the value is their email address?

Also, if the value is not in the list, is there an event I can handle that would let me add the item back to the datasource and then save it back up to the datasource when they hit a certain key? Or would I have to wire all that up manually?

Thanks!

Robert McLaws
AdvancedREI.com