Multiple page files used to be declared via core:pages in components.xml. With BETA1 that tag produces NPE:

Caused by: java.lang.NullPointerException
     at java.lang.Class.forName0(Native Method)
     at java.lang.Class.forName(Class.java:169)
     at org.jboss.seam.util.Reflections.classForName(Reflections.java:166)
     at org.jboss.seam.init.Initialization.installComponentsFromXmlElements(Initialization.java:252)
     at org.jboss.seam.init.Initialization.initComponentsFromXmlDocument(Initialization.java:161)
     ... 138 more

References does not provide information about multiple pages configuration. Please help!
BTW NPE is not informative in that particular case. Please add more specific diagnostics.