GWT + GAE + High Replication

I'm sure I'm missing something obvious, but after looking for the answer for half an hour, I give up.

I'm trying to run a GWT application on a local appengine (development) server using intellij 12.

My GWT configuration uses Appengine Dev as the server (and this is the only option), but I see no way to pass a --high_replication flag, or the -Ddatastore.default_high_rep_job_policy_unapplied_job_pct=0 flag recommended by the docs on google.

Trying to create a new run configuration for "Google AppEngine Dev Server" doesn't help.  Adding --high_replication to the server parameters there results in the server not starting up (unrecognized flag).

I've been up and down the options everywhere I can think to look and nothing works.
I found http://forum.jetbrains.com/thread/PyCharm-715 as a reference for python, but I see no corresponding field in intellij.

What am I missing?