From: DeskNow Knowledge Base
http://www.desknow.com/kb/

How do I use a SSL certificate in pfx format with DeskNow?
http://www.desknow.com/kb/idx/13/190/article/

PFX is a common format for SSL certificates.

If you already have a SSL certificate in this format, you can easily use it with DeskNow following these instructions.

1. stop DeskNow
2. make a backup copy of C:\Program Files\DeskNow\conf\server.xml (/var/desknow/conf/server.xml)
3. edit the server.xml file and replace this text:
keystoreFile="conf/keystore"

with this:
keystoreFile="C:\mycertificate.pfx" keystoreType="PKCS12" keystorePass="my_cert_password"
4. start DeskNow

If you do not have an SSL certificate yet, please see the Administration manual on how to obtain an SSL ertificate and use it with DeskNow.