InstallShield-2009 Premier: Basic msi project:

What to do when I want a custom action to run when user clicks cancel button during uninstall?

I put a custom action (a C# exe which would just show a message box) with

Action Type:

Type: Launch an executable

Location: Stored in the Binary table

Action Parameters:

Source: exe path

Target: a b c (doesn't matter, I don't need it)

Additional Options:

Return Processing: Synchronous (Check exit code)

Run Only During Path Uninstall: unchecked

Respond Options:

In-Script Execution: Rollback Execution in System Context

Executing Scheduling: disabled

Insert into Sequence:

Install UI-Sequence: <Absent from sequence>

Install Execute Sequence: After InstallServices (what should I set here?)

Install Execute Condition: (do I need to set? I left it blank)

but it didn't fire the message box when I canceled the uninstall. How?