Re: "This connection is untrusted" - Certificate Problem
WebInspect does not use the IE browser, but its own internal-yet-equivalent one, and this includes the acceptance of certificates. In actual use, the scanner simply accepts all certs and moves on, as its aim is to scan and not be a safe browser.
The complication here may be in the Macro Recorder and the replay of your Macro. I would record the macro, but then mark any certificate acceptance sessions as "Optional". With this edit, those sessions can either be present or not during the actual replay of the Macro during the live scan, and it will not affect the replay.
-- Habeas Data Micro Focus Fortify Customers-Only Forums – https://community.saas.hpe.com/t5/Fortify/ct-p/fortify