Appending JVM parameter to the parameter specified explicitly in plugin configuration?

Question

Sometimes I need the parameter to be appended, instead of overriding the one in configuration:

for instance

mvn test  -DargLine="-Dportal.test=huge"    

should be added to

<argLine>-XX:+CMSClassUnloadingEnabled</argLine>

so the result would equal to

<argLine>-XX:+CMSClassUnloadingEnabled -Dportal.test=huge</argLine>

Could please anybody tell me if it is possible and how ?

EDIT: Please don't answer with " Why would you want to do that" kind of annoying questions.

Answer 1

I have never used argLine but maybe this is what you are looking for.. i.e.:

<argLine>-DskipTests=true ${argLine}</argLine>

(I used skip tests as an example :))