Looking into this some more, I found the following page on Microsoft's site:
http://www.microsoft.com/technet/prodtechnol/sppt/reskit/c4061881x.mspx
According to this site, only certain fields from Outlook's contacts will import into SharePoint. Apparently if your field is not in the list, you are out of luck:
It is not possible to add new fields to the import list. Even though GAL entries include Web Page and Notes fields, Windows SharePoint Services does not import information from those GAL fields, even though it does import that information from Outlook contacts. Also, Windows SharePoint Services does not import the Full Name value from either Outlook contacts or GAL entries.
Based on that, it sounds like it is a limitation of both Outlook and SharePoint... Outlook doesn't provide a GAL (Global Address List) view of all of a contact's fields, and SharePoint doesn't support all of the GAL's that are provided (namely Notes and Web Page)
Here is the list of what is supported:
- First Name
- Last Name
- Company
- Job Title
- Business Phone
- Home Phone
- Mobile
- Business Fax
- Street Address
- City
- State
- Zip/Postal Code
- Country/Region