Hi
just to sum up if i understood what it is you want:
You want to retrieve the SPS internal ID of the manager because you want to filter your SPS list by who ever is logged on.
As the HowTo specifies, the filtering needs to be done on the ID rather than the user name.
Fetching this info could be done in a number of ways.
One could be using the GetUserInfo or GetUserCollectionFromSite methods of the "Users and Groups" SPS web service (_vti_bin/UserGroup.asmx) depending on if you need all users or a info about a specific user.
Jan Tielens made an example of how to populate a dropdown using GetUserCollectionFromSite here:
http://weblogs.asp.net/jan/archive/2004/03/16/90533.aspxhth
AndersR
//AndersR