system property not accessed by third-party application

[crash.test.dummy]

hi,
i have an application (packaged in a jar) that uses a system
property:

java -jar -Druntime.environment=TEST MyApp.jar

no problem accessing the runtime.environment property within the
MyApp application.

this application uses a third-party application (alias TPA, packaged
also in a jar) that uses the same runtime.environment property.
however, when the TPA accesses this property, the value is null.

if i run this TPA independently, specifying the property, it works
fine:

java -jar -Druntime.environment=TEST lib\ThirdPartyApp.jar

any ideas on what i may be doing wrong?
thanks.