Rangers managed a 2-0 semi-final victory over St Johnstone in the Co-operative Insurance Cup and is set to face St Mirren in the final next month.
“It’s never impossible until you can’t do it,” he said.
“If you’re at the Old Firm, you’ve got to set out at the start of every season and have a target of trying to win the domestic trophies.
“Trebles are never easy to win – I know that myself through past experience.
“So we’ll carry on as we’re doing and try to win the games as they come along and hope that that’s good enough for us.
“This spell that we’re having and the problems we have, if we do take injuries, it could ruin the season for us.
“But that’s in the background just now.
“We’re enjoying the fact that we’ve got to the first cup final of the season and we’ll look forward to that.”
