Set javaOptions in Test for Play/SBT

I configured build.sbt for the unit test to use a different Play (2.3.9 for Scala) configuration via,

javaOptions in Test ++= Seq("-Dconfig.file=/home/kitty/acme/test/resources/test-application.conf")

Play did not pick up test-application.conf and used application.conf in conf instead. AFAIK, there is no scalaOption in this case. However, if I include -Dconfig.file in the command line, it works fine,

sbt test -Dconfig.file=/home/kitty/acme/test/resources/test-application.conf

How do I fix this? Thanks.