Modeless Balloon not closed in vb addin

[olivier anguenot]

Hello,

I have a vb addin (registered under Outlook 2000) which display a
balloon when outlook starts.
The problem is that if the balloon is modeless, when I click on the
balloon button nothing happens (callback function is not fired). I
have only an event on AddinsUpdate().

Here is my code

Private Sub IDTExtensibility2_OnConnection(...)

ShowSimpleMessage "myMessage"

End Sub

Public Sub ShowSimpleMessage(Message As String)

If Not (gNameSpace.Application.Assistant Is Nothing) Then '
Set myBalloon = gNameSpace.Application.Assistant.NewBalloon
myBalloon.Animation = msoAnimationGetAttentionMajor
myBalloon.Heading = "strPIMphonyCompleteName"
myBalloon.Text = Message
myBalloon.Button = msoButtonSetOK
myBalloon.BalloonType = msoBalloonTypeButtons
myBalloon.Mode = msoModeModeless
myBalloon.Callback = "ProcessPrinter"
myBalloon.Private = 100
myBalloon.Icon = msoIconTip
myBalloon.Show
End If

End sub

Public Sub ProcessPrinter(bln As Balloon, lbtn As Long, lPriv As Long)

bln.Close

End Sub

I don't understand why ProcessPrinter is not fired. Is modeless
balloon not supported in vb addin or only supported in outlook macro ?
What's wrong in this code ?

Thanks in advance for any response.

Olivier Anguenot