git push doesn't honor .git/config

I renamed a local branch from MIS-59 to MIS-59_project, and did the following:
  git branch --set-upstream MIS-59_project origin/MIS-59
  git push --set-upstream origin MIS-59_project:MIS-59

However, .git/config is not being honored by git push; I have to supply all the parameters to actually push changes.

(MIS-59_project)$ git branch -v
  MIS-38_labor_cat    cab4fe6 [MIS-38] Create Master Labor Category import SQL
  MIS-39_org          02f9e2f [MIS-39] Create Unanet's Organization export SQL
  MIS-40_approval_grp 7c3b5ec [MIS-40] Create Unanet Approval Groups import SQL
  MIS-41_location     8bd55ab [MIS-41] Create Unanet Master Locations import SQL
  MIS-42_person       9fb1901 [MIS-42] Create SQL for Unanet's Person import
* MIS-59_project      ed3acc9 [ahead 1] [MIS-59] Switch to using
get_project_type_unanet()
  MIS-65_task         651a05b [MIS-65] Switch to using get_project_type_unanet()
  master              e98c105 Retired OTL
(MIS-59_project)$ grep -A2 MIS-59_project .git/config
[branch "MIS-59_project"]
        remote = origin
        merge = refs/heads/MIS-59
(MIS-59_project)$ git push
Everything up-to-date
(MIS-59_project)$ git branch -v
  MIS-38_labor_cat    cab4fe6 [MIS-38] Create Master Labor Category import SQL
  MIS-39_org          02f9e2f [MIS-39] Create Unanet's Organization export SQL
  MIS-40_approval_grp 7c3b5ec [MIS-40] Create Unanet Approval Groups import SQL
  MIS-41_location     8bd55ab [MIS-41] Create Unanet Master Locations import SQL
  MIS-42_person       9fb1901 [MIS-42] Create SQL for Unanet's Person import
* MIS-59_project      ed3acc9 [ahead 1] [MIS-59] Switch to using
get_project_type_unanet()
  MIS-65_task         651a05b [MIS-65] Switch to using get_project_type_unanet()
  master              e98c105 Retired OTL
(MIS-59_project)$ git push origin MIS-59_project:MIS-59
Counting objects: 11, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (6/6), 498 bytes, done.
Total 6 (delta 2), reused 0 (delta 0)
=> Syncing Gitorious... [OK]
To git@gitorious.burnsmcd.com:~plawrence/mis/plawrences-ora-apps.git
   1fbf2e0..ed3acc9  MIS-59_project -> MIS-59
(MIS-59_project)$

Did I miss something, or is this incorrect behavior? BTW, I'm running msysgit 1.7.0.2-preview20100309 on Windows XP.

Thanks, Phil Lawrence