JSF 1.2 can be used in EAP 6, but needs to be configured in jboss-deployment-structure.xml: https://access.redhat.com/documentation/en-US/JBoss_Enterprise_Application_Platform/6.3/html-single/Migration_Guide/index.html#sect-JSF_changes

<jboss-deployment-structure xmlns="urn:jboss:deployment-structure:1.0">
​ <deployment>
​ <dependencies>
​ <module name="javax.faces.api" slot="1.2" export="true"/>
​ <module name="com.sun.jsf-impl" slot="1.2" export="true"/>
​ </dependencies>
​ </deployment>
​ <sub-deployment name="jboss-seam-booking.war">
​ <exclusions>
​ <module name="javax.faces.api" slot="main"/>
​ <module name="com.sun.jsf-impl" slot="main"/>
​ </exclusions>
​ <dependencies>
​ <module name="javax.faces.api" slot="1.2"/>
​ <module name="com.sun.jsf-impl" slot="1.2"/>
​ </dependencies>
​ </sub-deployment>
​</jboss-deployment-structure>