Howarth said, "It was great to get the guys together and run through a few moves and generally get the travel and recent games out of their bodies". Casey felt the session was important as "the boys got to go through some basic drills that will form the building blocks for everything we do this week".
The session came on the back of Saturday's visit to the Millennium Stadium to watch the Wales v Australia game.
Islanders coach Pat Lam said "I was impressed with many aspects of the Welsh play especially the way they came back towards the end of the first half".
"They have a number of world class players and seem to have discovered some great new talent as well. The Welsh represent a significant challenge for us next weekend but we have assembled a squad of talented players who will provide stern opposition."
Lam himself played his last ever game at the Millennium Stadium for the Barbarians side scoring a try in the final minute of play.
"I have enormous love for Wales and the Welsh people. They were among the first top tier nations to recognise the rise of Pacific Islander rugby and we share a common passion for the game."