Unfortunately it is not possible.
Uninstalling is very different comparing to the other deployment scenarios. You probably noticed that all MSI authoring solutions support building Install/Repair UI but not the Uninstall one. It is because during the explicit uninstall no UI associated msi file is shown. MSI runtime displays a standard uninstall progress dialog instead. This is what is preventing Burn bootstrapper from displaying any msi UI on uninstall.
This therad also talks about the same issue: http://stackoverflow.com/questions/17808741/how-can-i-display-my-msis-ui-on-uninstalling-from-a-burn-bootstrapper
Uninstalling is very different comparing to the other deployment scenarios. You probably noticed that all MSI authoring solutions support building Install/Repair UI but not the Uninstall one. It is because during the explicit uninstall no UI associated msi file is shown. MSI runtime displays a standard uninstall progress dialog instead. This is what is preventing Burn bootstrapper from displaying any msi UI on uninstall.
This therad also talks about the same issue: http://stackoverflow.com/questions/17808741/how-can-i-display-my-msis-ui-on-uninstalling-from-a-burn-bootstrapper