Error Editing SSIS Pkg In BIDS

We are using SQL Server 2005 Workgroup Edition SP2. I have a fixed-length flat file import spec created in SQL Server Mgmt Studio using the Import wizard. I then created an Integration Sevices project in BIDS and added the existing SQL Server package created with the wizard to the project. When I try to edit the package with the SSIS designer, it does not appear to handle the package properly. That is, only some of the fields are selected (and when I select all the available fields, still only some show up in the detail pane of the Input Columns tab), the data types are incorrect, and the starting location (it's a fixed length file, remember) for each field (LineageID?) is incorrect. My understanding is that, with Workgroup Edition, there are only two ways, other than say programmatically from a VB program, to run the package: (1) by creating a SQL Agent job or from a BIDS project. I have seen a Cumulative Update package (#2) for SP2 that mentions some problems in BIDS' handling of SSIS pkgs, but the symptoms are in no way similar to this. Can anyone tell me what is going on here?? Thanks.

Paul