Problem with Ear plugin earlib, files are not included

I have somewhat interesting project structure in the gradle build(remaking the build from old ant files to gradle):

Project1
|
project11 (root project)
| libs
|
project12

Project2
|
project21
|
project22 (project which creates an ear and needs to include project11/libs)
| lib

Now when I try to use the ear plugin in project22 like this:

dependencies {
    earlib fileTree(project11_libs).include('service.jar,another-service.jar') //These are missing from the ear!!!
    earlib fileTree("lib").include('*.jar') //These appear nicely
    deploy project(path: ':Project1:project12:some.war', configuration: 'archives') //war file appears nicely
}

the jar files from project11_libs (pointing to rootProject/libs dir) are not included. I get the jar files from the project22(ear project) lib alright and also the war file from project12. I am wondering does that have something to do that the jars in the project11_libs are produced by other projects?

I tried to make sure they are ready by placing the ear as the last task:
clean cleanJar cleanWar cleanEar createDirs classes jar war test ear

I am running the build from jenkins.
Google did not help this time(or I did not have the right words to look for), although I have managed quite well until this just by searching. And yes, I have been playing with gradle only a short time so this is all new to me.

The cause for this appeared to be wrong include syntax:

.include(‘service.jar,another-service.jar’) shall be .include(‘service.jar’, ‘another-service.jar’) and I get all the needed stuff.