I had to convert a Wise MSI project to InstallShield several years ago. I had to manually convert everything. Since this is a MSI to MSI conversion - for the most part, just document your UpgradeCode and make sure you set the same in InstallShield Next comes the pain staking part, copying component guids between Wise and InstallShield. Finally, converting custom actions from Wise to InstallShield.
Even with trying to be careful, I still ran into a problem 'upgrading' previous versions installed using Wise. The problem would always occur when trying to validate the installer - it would hang indefinitely. In the end I had to create a custom action that checks for a previous install, gets the uninstall string from the registry, and manually uninstall the 'earlier version'.
