Dewey was the joint top try-scorer in BT Premiership Division One in 2004/05 with 16 tries for Heriot's and made four appearances - including two starts - for Edinburgh before accepting a contract with the professional team ahead of last season.
He was a key member of the Scotland squad during the 2004 IRB Under-21 World Championship in Scotland, the tournament which saw Ireland finish as runners-up to New ealand.
Dewey travelled to South Africa with the Scottish squad on the 2006 summer tour, but did not play in either Test match but has since been involved in Scotland's Six Nations campaign this season and scored a try against England at Twickenham earlier this month, in the dying moments of the game.
Ulster Rugby is also pleased to announce that Carey, the former 'Quins front rower, is returning to Belfast from English side Rotherham Titans. He has signed a two-year contract with Ulster.