Because a transport is bound to a cache container only if there are clustered caches in the initial configuration, adding a clustered cache to such a cache container will result in Infinispan complaining about not having a transport.
This can be solved by either always starting with a transport, or by making a distinction between local and clustered cache containers.
Furthermore, making a clustered cache EAGER within the configuration XML file (they are LAZY by default), will trigger this problem even on startup:

MSC00001: Failed to start service jboss.infinispan.sfsb.repl: org.jboss.msc.service.StartException in service jboss.infinispan.sfsb.repl: Failed to start service
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1780) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [:1.6.0_29]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [:1.6.0_29]
at java.lang.Thread.run(Thread.java:662) [:1.6.0_29]
Caused by: org.infinispan.config.ConfigurationException: Cache cannot use a clustered mode (REPL_ASYNC) mode and not define a transport!
at org.infinispan.config.Configuration.assertValid(Configuration.java:1664)
at org.infinispan.manager.DefaultCacheManager.wireCache(DefaultCacheManager.java:683)
at org.infinispan.manager.DefaultCacheManager.createCache(DefaultCacheManager.java:645)
at org.infinispan.manager.DefaultCacheManager.getCache(DefaultCacheManager.java:541)
at org.infinispan.manager.DefaultCacheManager.getCache(DefaultCacheManager.java:555)
at org.jboss.as.clustering.infinispan.DefaultEmbeddedCacheManager.getCache(DefaultEmbeddedCacheManager.java:118)
at org.jboss.as.clustering.infinispan.DefaultEmbeddedCacheManager.getCache(DefaultEmbeddedCacheManager.java:109)
at org.jboss.as.clustering.infinispan.subsystem.CacheService.start(CacheService.java:80)
at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1824) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]
at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1759) [jboss-msc-1.0.1.GA.jar:1.0.1.GA]
... 3 more