1.
svn cp  svn+ssh://svn.code.sf.net/p/gate/code/gate/trunk svn+ssh://svn.code.sf.net/p/gate/code/gate/branches/termraider-refactor

2.
svn switch  ^/gate/branches/termraider-refactor

3. 
make all the changes, intermediate commits, etc., until done

4. 
svn sw my local copy back to the trunk

4a.
svn up

5.
svn rm  TermRaider
svn cp  svn+ssh://.../termraider-refactor/plugins/TermRaider  .

6.
svn rm the old branch