Please follow these instructions to install your SSL certificate on Microsoft ISA Server 2004 & 2006:
Launch the MMC
If IIS and ISA are on the same server, go directly to step 3.
1. Start > Run > MMC.
2. Go to File and choose Add/Remove Snap in.
3. Choose Add, click Certificates in Standalone Snap-in and then click Add.
4. Choose Computer Account and click Next.
5. Choose Local Computer and click Finish.
Import the .pfx file
The .pfx file is the file containing the certificate and the private key.
1. Go to Personal and then Certificates.
2. Right-click, choose All taks and Import.
3. Select the file to import.
4. Keep the values as default.
Configure Microsoft ISA Server 2004 or 2006
1. Launch ISA Server Management (located in Start > All Programs > Microsoft ISA Server).
2. Click + next to Microsoft Internet Security and Acceleration Server.
3. Right-click on your server name and click Properties.
4. Go to Security and click Import SSL Certificate.
5. Select your SSL certificate file and click Open
6. Click Finish.