Incremental hg convert - switching subversion sources

[Paul Moore]

I have a Subversion repository I want to mirror. To speed up the
initial conversion, I have used svnsync to create a local mirror of
the remote repository (which I can only access via http).

I can create my local Mercurial repository via

    hg convert file:///path/to/my/svn/mirror my-hg

Once the initial repository has been created, I can update it by doing
a svnsync to update the local mirror, and then hg convert to
incrementally pull into hg. What I'd like to do, however, is to drop
the svn mirror after the original conversion, and do future updates
via hg convert direct from the http source.

Is this possible, in any way? I didn't manage to do this in my initial
experiments - the convert from http pulled everything, resulting in a
repository with 2 branches, the first being the initial pull, and the
second being a complete pull of the http repo. I presume that
subsequent converts will incrementally update the branch that came
from http, but the benefits of the local mirror for the initial pull
are lost (and for a "real" case, doing the initial pull from http
simply isn't going to be practical).

Can anyone help? Is there a way that I can do this?

Thanks,
Paul.