Custom List form - Autopopulate Manager

Question

Hi,

I have a Sharepoint 2007 custom list with a column named 'Manager', to hold the user's Manager (single line of text).

When creating a new item I want the NewForm.aspx to autopulate the Manager field with the user's manager.

I know we can autopulate list form fields using JQuery to access Sharepoint's 'User Information List' exposed as a webservice, as Marc's blog below:

http://sympmarc.com/2010/04/29/populating-a-sharepoint-list-form-with-the-current-user-information/

My problem is the Manager is not stored in the 'User Information List' so I can not retrieve it as above, anyone have any ideas?

Thanks, Nav