Publisher Addins Built With VS2005 Don't Work in Publisher 2003

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I have just upgraded Visual Studio from 2003 to 2005 and am in the process of
converting my VB applications. Most conversions have gone quite smoothly.

However, I have several Add-Ins that I developed to add button bars to
Publisher 2003. When built these under VS 2003, they worked. I used the
conversion wizard in VS 2005 to convert them. I then rebuilt and installed
them. They refused to work in Publisher. I checked the registry and it
appeared that the install was clean.

I notice that there were two warnings (see below) that were generated in the
builds, so I decided to try creating a small add-in from scratch. Using the
Shared Add-in template under the Extensibility section of Other Project
Types, I specified that I wanted to develop in VB and that the solution would
be used by Publisher alone. The generated code did not have the warnings
that my old add-in was showing. I made sure that the proper references,
imports, etc. were all specified. I added msgbox displays to each of the
event sections. I did not add any other code. I built and installed this
solution, then started Publisher... Nothing.

I have searched every possible help source that I can find and cannot find
anything that directly addresses this problem. I noticed that VSTO is
mentioned a lot. I am having trouble understanding what it will do for me,
if anything. I cannot find any mention of it working with Publisher.

1. Does anyone have any idea as to how I can get these add-ins to work?
2. What exactly, if anything, will I gain by downloading VSTO? (I am not
eager to give up another 2 gigs of my C: drive, if I can avoid it.)

The two warnings that I got after I converted one of the add-ins were:

"Type of parameter 'RemoveMode' is not CLS-compliant "

in the following code:

Public Sub OnDisconnection (ByVal RemoveMode As
Extensibility.e xt_DisconnectMo de, _
ByRef Custom As System.Array) _
Implements Extensibility.I DTExtensibility 2.OnDisconnecti on

and...

"Type of parameter 'ConnectMode' is not CLS-compliant "

in this code:

Public Sub OnConnection(By Val Application As Object, _
ByVal ConnectMode As Extensibility.e xt_ConnectMode, _
ByVal AddInInst As Object, ByRef Custom As System.Array) _
Implements Extensibility.I DTExtensibility 2.OnConnection

Any assistance will be greatly appreciated.

Thanks,

Mark.

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Mark