Central Bazaar Repo Syncing with SVN

We are in the process of reviewing new version control options as our current system, SVN, is lacking some features we require. Bazaar seems to be the best option in terms of stability right now- git and hg's GUI tools crash or lack critical features or are just too complex to setup.

We need a process that allows us to continue to use SVN but review the features/stability of BZR/TortoiseBZR/etc.

In order to achieve this, we have setup a central bazaar repository which was an import from our existing SVN repository- so it has full history, etc.

Individual developers then branch from the bazaar repository and do their work, branches, etc.

So the ideal workflow for us is:

Develop in working tree on local branch-> commit locally->..(repeat x times)...-> push to central -> ..(repeat y times).... -> Sync Changes with SVN

We've already had some problems when the SVN repo changes before after a pull is done with 'pending commits' in the bazaar world. I think in this case we need to be rebasing before sending data to SVN as this seems to put the version history in the order SVN expects- is this correct?

Secondly, I guess we need to do the rebase on the central repository- I've been doing it on my local bzr branch (which works), but this isn't practical- e.g. if I push from local->central before I do an update in central from svn I have to mess around with undoing changes, etc.

My central repo is currently created without a working tree- was this wrong? Do I need to create a working tree for the central repo? Without it I don't seem to be able to do a rebase? If I do need it, how can I create it without having to re-import from SVN as this took days!

Any help / advice would be great- thanks.