AppleShare file server entries can be added to the Key Chain in two ways:
1) Access the server via an alias. You will then be provided with the dialog asking if you want to add that server to your Key Chain.
2) Access the server via AppleTalk Catalogs. When you search through the catalog for an AppleShare server, and select one, You will then be provided with the dialog asking if you want to add that server to your Key Chain.
PowerTalk uses the Alias Manager to trigger the additional dialog allowing you to add the server to your keychain. The Chooser does not use AppleEvents, nor the Alias Manager, and therefore has no way to trigger the dialog.
Note: Once added to your Key Chain the logon dialog box for a server will be skipped when accessing via an alias or AppleTalk Catalogs. Access via the Chooser still requires entry of user name and password.