I have an early model shimano freehub with a 6 speed uniglide cassette. I would like to upgrade to a hg cassette. The problem is that, according to Sheldon Brown, this is not possible since my hub body does not have a "bulge"; meaning I cannot swap freehub bodies. I would really like to avoid buying and installing different hubs. Has anyone discovered a work around for this problem, or am I stuck with this lacklustre cassette for the time being?