If you want to try this organ, be sure you have Hauptwerk v4 or higher (this organ will work with the Free Edition and does not require a special dongle file) and have already installed the Pitea organ from Al Morse's web site.
Then download the following:
Hauptwerk Installation rar
This is a Hauptwerk standard installation package in rar format. Save it to your disk, start Hauptwerk, and then use its install feature to read the rar file as per the manual.
I have heard from some users (outside the USA) that you might need to disable the "wind model" for the organ to play properly. Since I am in the USA I cannot test this - but it sounds reasonable.
CODM Source File
This one is optional. I provide the source code for the Hauptwerk editor so you can see how I did all this and get ideas for your own projects. You will have to rename this file after downloading to "Les-945-v2_0.CustomOrgan_Hauptwerk_xml." I could not get the download function to work properly with the new extra-long file extension required by Hauptwerk 4!
This organ is a great value. You get ~80 ranks for free (I get nothing - but I have great a day job). Since the samples are 16-bit, the instrument fits into RAM on all but the very smallest computers. The reverb on the samples is more than adequate for practicing. I add additional convolutional reverb on my recordings.
There are some demo recordings of this instrument on my organ recordings page.
Have fun with this.