Resolution:
Yes. Below are the steps which will help you to start the JBOSS server by using the unjar option.

First please make sure that your JBOSS is working with the ECM.ear file.
If it works then follow the below steps.

1. Go to the /jboss/server/&ltservername>/deploy directory.
2. Rename the ECM.ear file to ECM.ear.test
3. Then in the deploy directory type 'mkdir ECM.ear' (This will create a ECM.ear directory)
4. go inside the ECM.ear directory and type 'jar -xvf ../ECM.ear.test' (This will extract all of the files from the ECM.ear file into this directory).
5. Inside the ECM.ear directory rename the file EML.war to EML.war.test and then create a directory called EML.war 'mkdir EML.war' (This directory will be inside the ECM.ear directory)
6. Go inside the EML.war directory and type 'jar -xvf ../EML.war.test' (This will extract all of the files from the EML.war into this directory)
7. Now inside this directory there will be a directory called 'css' and you can modify this file if you want.
8. Before you start the deploy please remove the ECM.ear.test file from the deploy directory and the EML.war.test file from the ECM.ear directory.

I hope this helps, if you have any questions please ask Support.

Thanks.

Can I start a JBOSS server by extracting the contents of the ECM.ear file