On the Windows Start menu, click All Programs > Microsoft Lync Server 2010 > Lync Server Deployment Wizard.
In the Lync Server 2010 – Deployment Wizard, click Install or Update Lync Server System.
Under Step 3: Request, Install, or Assign Certificates, click Run.
In the Certificate Wizard, select External Edge certificate (public internet) and then click Import Certificate.
On the Import Certificate page, enter or browse for the location of the certificate file.
If you used the Lync interface to create the CSR, the certificate file is a .cer file (i.e. yourdomain_com.cer).
If you used the IIS to create the CSR, the certificate file is a .pfx file (i.e. yourdomain_com.pfx).
If you are using a .pfx file, check Certificate file contains certificate’s private key.
If you are using a .cer file, do not check this box.
Click Next.
On the Import Certificate Summary page, verify that the information is correct, and then click Next.
On the Executing Commands page, verify that the Task status is Completed, and then click Finish.
In the Certificate Wizard, select External Edge certificate (public internet) and then click Assign.
On the Certificate Assignment page, click Next.
On the Certificate Store page, click View Certificate Details to verify that you installed the correct certificate.
In the Certificate window, review the certificate information, and then click OK
On the Certificate Store page, click Next
On the Executing Commands page, verify that the Task status is Completed, and then click Finish.
On the Certificate Store page, click Next.
To verify that your certificate was properly installed, in the Certificate Wizard, make sure that the status of the External Edge certificate (public internet) is Assigned.
Your SSL certificate has been successfully installed and assigned.
