You can, on most screens, if you call the SetCertificatesFile() method of the ifHttpAgent interface. It's no different than requesting https URLs with the roUrlTransfer.
“But Mr. Dent, the plans have been available in the local planning office for the last nine months.”
“Oh yes, well, as soon as I heard I went straight round to see them, yesterday afternoon. You hadn’t exactly gone out of your way to call attention to them, had you? I mean, like actually telling anybody or anything.”
“But the plans were on display . . .”
“On display? I eventually had to go down to the cellar to find them.”
“That’s the display department.”
“With a flashlight.”
“Ah, well, the lights had probably gone.”
“So had the stairs.”
“But look, you found the notice, didn’t you?”
“Yes,” said Arthur, “yes I did. It was on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard.’”
Why can't ifHttpAgent ensure that a (system) default certificate set is used if not overridden by user? I never had to manually add certificate chain in other programming environments.