SVN Merge Branch Into Previous Revision

We are customizing a software package (we have the entire sour开发者_Python百科ce). Our first SVN commit was vanilla version 3.0.0 of this package. Since then, we've made lots of little changes to it and a few fairly involved changes.

The vendor whose package we are customizing just released version 3.1.0. I'd like to get all of their fixes/improvements and retroactively apply mine so that they are not lost (as if we were working with 3.1.0 from the start).

I can do this manually per file, but is there a way to do this by merging the 3.1.0 changes into revision 1 of our trunk, and having it apply to the entire tree? Do I create a new branch for 3.1.0 and merge it into our 3.0.0 (+ our changes) branch?

Our commit history looks like this:

rev 01 - Original import of 3.0.0
rev 02 - Changes to 3.0.0
rev 03 - More changes to 3.0.0
...
rev xx - More changes to 3.0.0

Version 3.1.0 released <--- I want to merge this into rev 01 above basically..

Thank you!

Take a look at http://svnbook.red-bean.com/en/1.5/svn.advanced.vendorbr.html there it is proposed to do the merge the other way around. Get the new 3.1.0 sources into trunk, merge from your 3.0.0 branch head into 3.1.0 with revisions spanning the first to the last change you want to merge.