This post features a small tweak which I discovered following a link on one of Carl Stalhood’s awesome guides. However, I thought putting the content of some posts as well as my own research together might help some of you getting things in place more quickly.

Enable Rewrite feature

Create Rewrite Action

add rewrite action rw_act_insert_belowloginbtn insert_after_all "HTTP.RES.BODY(120000).SET_TEXT_MODE(IGNORECASE)" q{"var login_below_btn=$(\"<div style='text-align:center;margin-left:167px;padding-top: 60px;font-size:12px'><a href='https://yourlink.html' target='_blank'>My Link</a></div>\").appendTo(logonbox_logonform);"} -pattern "logonbox_logonform.append(box_view);"

Create Rewrite Policy

add rewrite policy rw_pol_insert_belowloginbtn "HTTP.REQ.URL.CONTAINS(\"gateway_login_view.js\")" rw_act_insert_belowloginbtn

Bind Rewrite Policy to your vServer

In Netscaler web interface, navigate to Netscaler Gateway > Virtual Servers > MyVirtualServer.
Add a rewrite Policy and choose the previously created Policy to bind to the vServer.
Make sure, that you bind the policy with type Response.

Pay attention to Cache Policies

Netscaler gateway vserver wizards automatically adds some cache policies, that may prevent the rewrite policy from being applied.

If “_cacheVPNStaticObjects” cache policy is bount to your vServer, edit it and change CACHE to NOCACHE

References

Original Post Netscaler 11 Theme Customization - How to Add Links and Verbiage