I ended up finding the source code to this utility and have made several updates:

• Allow reports larger than 64 bytes
• Fixed an error when re-connecting a device (which previously required a restart of the app)
• Made the window larger to accommodate for the larger reports

You can download my updated version and source code from:

SimpleHIDWrite3.zip
HIDKomponente.zip

Thanks to the original author of this tool.

EDIT: Source code is now available on GitHub here