Hello Brian,
Thanks for the continued interest in Hauptwerk.
Based on Roland's owner's manual for their PK-5:
https://www.roland.com/us/products/pk-5/
https://static.roland.com/assets/media/pdf/PK-5_OM.pdf
... I see that it it needs to connect to your computer using a MIDI cable. (It doesn't have a direct USB-MIDI connection.) Also, I see that it either needs to have its AC power adapter connector, or to have batteries (with charge) in it. Hence what you should need to do is:
- Make sure the PK-5's power adapter is connected, or that it has charged batteries in it.
- Make sure the PK-5 is switched on.
- Connect a MIDI lead from the MIDI OUT port on your PK-5 to a spare MIDI IN port on your PC's MIDI interface (and make sure the current version of the driver for your MIDI interface is installed, if relevant).
- Reboot the PC, for good measure.
- Launch Hauptwerk.
- Go to the 'General settings | MIDI ports | MIDI IN ports' screen.
- Make sure that the MIDI interface's MIDI IN port (to which your PK-5 is connected) is ticked in the left-hand ('Console MIDI IN') column.
- Click the OK button.
- Load the St. Anne's organ.
- Right-click on the virtual pedalboard, select 'Auto-detect MIDI ...', then follow the on-screen instructions to press the highest and lowest keys on your PK-5.
- The 'Done' button should become enabled, indicating that Hauptwerk has 'heard' valid MIDI messages from your PK-5. Click it.
You should then be able to play the virtual St. Anne's pedals from your PK-5. If so, perform the same auto-detection procedure in any other sample sets (organs) that you might use.
Does that solve it?