Are built-in properties always available?

In this article (http://www.jetbrains.net/confluence/display/TCD4/Predefined+Properties) it seems to say that there are pre-defined properties that are always available.

However, when running an msbuild build configuration with multiple targets (i.e., Build;Deploy), the second target is not properly evaluating this property: $(teamcity_build_changedFiles_file).  Why isn't this property available in the build?

Thanks,
Michael