Bart,
Yes, this should not require any toolkit.
Did you use the ExecWB method (attached image)? That's nice because you can suppress any user dialog box by choosing the "don't prompt user" enum, and it can be potentially used with more than just HTML files.
If someone is looking for a simple Windows method that doesn't require IE/ActiveX and works with any document that has a default application to handle it (not just HTML), then take a look at the
How Do I Print a File Programmatically From LabVIEW? KnowledgeBase document and try the lvwutil32 printing utility. Its drawback is that it's not easy to suppress the print dialog. But those Windows utilities are good things to be aware of anyway, so it might be worth checking out.
--John