VB6 Implements & events

I have an older VB6 project that I'm trying to add unit tests for. I was breaking dependencies in classes by mocking objects. Everything was going great until I found some dependencies that were raising events and now I've hit a wall.

Here's a quick example of what I'm trying to do that DOESN'T WORK:

ITab.cls:

Option Explicit

Public Event Click(tabNumber As Integer)

Public Sub SomeOtherFunction()

End Sub

clsRealTab.cls:

Option Explicit
Implements ITab

Public Event Click(tabNumber As Integer)

Public Sub ITab_SomeOtherFunction()
    'code here'
End Sub

frmMain.frm:

Option Explicit

Private WithEvents mTab as ITab

Public Sub Main()
    Set mTab = New clsRealTab 'gives "Object or class does not support the set of events" error'
End Sub

Does anybody know if there's a way to make this work or another way to go about handling this situation?

I implemented a callback interface that I called ITabEventsHandler. It looks like this:

Option Explicit

Public Sub Click(intPreviousTab As Integer, objSSTab As Object)

End Sub

Then I added Implements ITabEventsHandler to my form and pass the form as an ITabEventsHandler parameter to my clsTab initializer. Instead of raising a custom Click(...) event, I can just call mTabEventsHandler.Click(...).

Thanks for the suggestion!