You can use any VBScript commands you want in a custom action. Do you mean to ask what VBScript commands are available in InstallScript?You can write a CA completely in VBS, then just load it into the Binary table. I'm not familiar with Express, but ...
I see...using IS2008EX, I'm not sure. If there's no way to directly edit the tables, then it sounds like you're S-O-L.However, is it then possible, to build your app with IS 2008 EX so that it generates the MSI file (CD-ROM I think? network image?), ...
Create the MSI file as you normally would, then edit it with Orca. You can download that free here:http://www.technipages.com/wp-content/uploads/2007/11/orca.MsiYou can then directly edit your RemoveFile table and run your MSI as you wish.Don't be af...