It may not be a single property but may be a combination of several that uniquely identify the component. Without knowing the application, the component in question, etc., I cannot help with the specifics. However, I have found that there is usually a way to do so.
Something else you might want to consider in your mapping is taking a look at the "Required Children" feature of name mapping and, possibly, the "Conditional Mode" feature. Both of those give additional capabilities to name mapping so it is not as dependant upon just the static properties of the object.
For that matter, your WndCaption contains some common text. You could edit your NameMapping to wildcard your WndCaption as "*InstallShield*" which, in combination with something like WndClass and some other paramters, will uniquely identify your component.