There are many many scripts around which you can use to copy a folder. Add one as a Custom Action.

I'm wondering, though, why you'd need to perform this operation after the install is complete. Surely all the information that you'd need after completion is available beforehand and thus could be used to copy these files as part of the install.

 Yes, but how do you copy them to the installdir\EXAMPLEDIR?
The files needs to be copied after the installation has finished because they are specific for our company.

CustomAction? I dont want to make a .bat-file which copies the files manually to the target-dir.. But hopefully the msi-installation could do that somehow..

>The files needs to be copied after the installation has finished because they are specific for our company.

So I'm guessing you have a vendor-supplied MSI? Simple: add your cusom files with a transform. Remember that WPS will create an external CAB for these files so you'll need to distribute that CAB with the MSI/MST.

A custom action will be required to perform any installation steps after the installation has finished. Once InstallFinalize has completed, all rollback information is deleted and the availability of property values is also limited.
As VBScab has suggested, deploying the files using a transform is the most reliable way - and also offers the advantage that you don't need to script another custom action to handle the uninstall of the additional files.