I recently separated our company installers in to two features (one enabled and one absent), to allow the user to select both, I've used UI_Mondo GUI to allow selection.
I've managed to get our custom action to work if the feature is selected:
<Custom Action="RestartIISForASPNet4" After="AspnetRegIIS"><![CDATA[(NOT INSTALLED) AND (&WebServiceFeature=3) AND NOT (!WebServiceFeature=3)]]></Custom
I tried but for some reason it's coming up with false (IMO, it can't as in the log the WixUI_InstallMode is set to InstallComplete.
<Custom Action="RestartIISForASPNet4" After="AspnetRegIIS"><![CDATA[((NOT INSTALLED) AND (&WebServiceFeature=3) AND NOT (!WebServiceFeature=3)) OR WixUI_InstallMode = "InstallComplete"]]></Custom>
Anybody have any ideas what I'm missing, it's probably really obvious.