I just ran a quick test using cast, it seems to work for me. The timestamp info is just in a different format. Here's what I did for a test. Is this what you were looking for or if not, could you explain a bit further.
--
declare @test-2 varchar(5)
declare @test1 timestamp
declare @test2 varchar(5)
set @test-2 = '1ccm'
set @test1 = cast(@test as timestamp)
set @test2 = cast(@test1 as varchar(5))
select @test-2, @test1, @test2
-- Result --
----- ------------------ -----
1ccm 0x3163636D00000000 1ccm
(1 row(s) affected)