You can use the buildtools/userenv.properties file to override property settings that are common across all Commerce Reference Store modules. This includes properties that are specified in the Store/build.properties, common.properties, and environment.properties files. The sample-userenv.properties file, which you can use as a template when creating your own userenv.properties file, includes commented out versions of the properties that you are most likely to want to modify:

# Dynamo environment settings. Recommended that you set DYNAMO_HOME AND DAS_ROOT
# as environment properties for your OS. Id you don't set them in OS they can be
# specified here.
#
# dynamo.home=${env.DYNAMO_HOME}
# das.root.dir=${env.DAS_ROOT}

# Define modules that should be excluded from the default module list.
# exclude.modules=DCS-CSR/build.xml,Fluoroscope/build.xml,Mobile/build.xml

# The Flex details. Set tools.devsetup.buildFlexElements to true if you want Flex
# elements to be compiled during build process. Also specify the Flex home
# directory.
#
# tools.devsetup.buildFlexElements=true
# FLEX_DIR=/usr/local/flex_sdk_3.5

Note: To reconfigure module-specific properties, you must edit the module-name/build.properties files for the individual modules.