Using MSBuild 4.0
Even if the SignMsi target is overridden and SignOutput is set to true, the target is not called. I believe @(SignMsi) is not being set. It is set in wix2010.targets by the InscribeMsi task but this isn't called if the MSI has no external cabs. I think @(SignMsi) should be set even if InscribeMsi is not called.