For Gateway 9.2, there is a minimum Cumulative Release to be applied, as the Webstart Application was introduced only in CR2 and above.
In order to verify the CR currently installed, user can either check from ssgmenu > option 8) Display Patch Management menu > option 4) List Gateway patch history
Alternatively the following command can be ran at the prompt: /opt/SecureSpan/Controller/bin/patch.sh list
Here an example:
# /opt/SecureSpan/Controller/bin/patch.sh list
Patch ID CA_API_Gateway_v9.2.00-CR07 (Upgrades the CA API Gateway Software to version 9.2.00-CR07. This patch requires a reboot of the CA API Gateway Appliance after installation.) is INSTALLED, last modified on 2018-09-14T17:07:34+1000
If a CR2+ is installed, the Webstart Application directory and its libraries are created in the Gateway file system:
# ls -la /opt/SecureSpan/Gateway/runtime/web/ssg/webstart/
drwxr-xr-x 4 layer7 layer7 4096 Sep 14 17:07 .
drwxr-xr-x 4 layer7 layer7 4096 Sep 14 17:07 ..
drwxr-xr-x 2 layer7 layer7 4096 Sep 14 17:07 lib
-r--r--r-- 1 layer7 layer7 8883 Dec 26 2017 manager.jnlp
drwxr-xr-x 2 layer7 layer7 4096 Sep 14 17:07 resources
SOLUTION: In order to launch Gateway 9.2 Policy Manager via Webstart Application, please install CR2 or higher.