This is one of many areas of standalone.xml that do not appear to support property values (expressions) in this build. The exception is the following:

org.jboss.as.controller.persistence.ConfigurationPersistenceException: JBAS014676: Failed to parse configuration
at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:141) [jboss-as-controller-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.server.ServerService.boot(ServerService.java:305) [jboss-as-server-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.controller.AbstractControllerService$1.run(AbstractControllerService.java:185) [jboss-as-controller-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_09-icedtea]
Caused by: java.lang.IllegalArgumentException
at org.jboss.dmr.ModelValue.asInt(ModelValue.java:58) [jboss-dmr-1.1.3.Final.jar:1.1.3.Final]
at org.jboss.dmr.ModelNode.asInt(ModelNode.java:226) [jboss-dmr-1.1.3.Final.jar:1.1.3.Final]
at org.jboss.as.ejb3.subsystem.EJB3Subsystem12Parser.parseStrictMaxPool(EJB3Subsystem12Parser.java:484)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem12Parser.parseBeanInstancePools(EJB3Subsystem12Parser.java:459)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem12Parser.parsePools(EJB3Subsystem12Parser.java:442)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem12Parser.readElement(EJB3Subsystem12Parser.java:154)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem13Parser.readElement(EJB3Subsystem13Parser.java:71)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem14Parser.readElement(EJB3Subsystem14Parser.java:56)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem12Parser.readElement(EJB3Subsystem12Parser.java:128)
at org.jboss.as.ejb3.subsystem.EJB3Subsystem12Parser.readElement(EJB3Subsystem12Parser.java:84)
at org.jboss.staxmapper.XMLMapperImpl.processNested(XMLMapperImpl.java:110) [staxmapper-1.1.0.Final.jar:1.1.0.Final]
at org.jboss.staxmapper.XMLExtendedStreamReaderImpl.handleAny(XMLExtendedStreamReaderImpl.java:69) [staxmapper-1.1.0.Final.jar:1.1.0.Final]
at org.jboss.as.server.parsing.StandaloneXml.parseServerProfile(StandaloneXml.java:1028) [jboss-as-server-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.server.parsing.StandaloneXml.readServerElement_1_4(StandaloneXml.java:449) [jboss-as-server-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.server.parsing.StandaloneXml.readElement(StandaloneXml.java:136) [jboss-as-server-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.as.server.parsing.StandaloneXml.readElement(StandaloneXml.java:103) [jboss-as-server-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
at org.jboss.staxmapper.XMLMapperImpl.processNested(XMLMapperImpl.java:110) [staxmapper-1.1.0.Final.jar:1.1.0.Final]
at org.jboss.staxmapper.XMLMapperImpl.parseDocument(XMLMapperImpl.java:69) [staxmapper-1.1.0.Final.jar:1.1.0.Final]
at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:133) [jboss-as-controller-7.2.0.Alpha1-SNAPSHOT.jar:7.2.0.Alpha1-SNAPSHOT]
... 3 more