Think this is more Java question, and workaround should be affecting the JRE.
Not sure if this will work in your case, but possible solution is to import this certificate into the JRE keystore.
Generic description can be found at Sun website. Though process is pretty simple.
First you should navigate the needed HTTPS URL with your browser and export the cert using SSL properties (don't remember how it is done in IE, but in Firefox something like Security > View cert > Details > Save as -- still not sure because using non-English licalization), any X.509 type should work.
Next you should import it using keytool. Navigate to the current CF JRE's bin, execute the following command (replace arguments with your values) and restart CF:
keytool -keystore <path to keystore> -import -file <path to certificate> -alias <alias>
BTW, there is a UI tool for this, but I haven't used it so can't say if it works fine.