[wix-users] how to switch a button on a dialog? (Modifying WiX dialogs)

[Alan Sinclair]

How do I switch a button from ElevationShield="yes"  to
ElevationShield="no" ?

My installer needs to check whether to install per-user or per-machine but
has no other configurable properties, so I've copied and changed
WixUI_Advanced to have InstallScope as the final dialog (omitting Install
Destination and Features dialogs). The dialog sequence now has just EULA
then InstallScope.

The new version of InstallScope has an Install button (in place of Next),
and the RadioButtonGroup for selection of per-user vs per-machine.

Is it possible to switch the Install button's ElevationShield status
between "yes" and "no" (i.e. switch the graphic to show/hide a shield)
depending on the user's choice of install scope? That is, if the user
chooses per-user then the Install button should not have the shield, and
vice-versa.

If it is not possible to switch the button status then is there a standard
WiX dialog I can end with, which just says something like "ready to
install"., and show the appropriate Install[NoShield] button on that?

thanks!
Alan