Tested with seam-persistence-3.0.0-SNAPSHOT and everything works fine, I suspect the issue was with an earlier version of seam-persistence.

I can still see the issue. I am using seam-remoting snapshot which currently uses seam-persistence Beta4 (released 2011-02-08)

I believe this is browser/locale specific

I can see the following exception when any of the operations mentioned above is executed:

19:40:50,254 ERROR [org.jboss.seam.remoting.Remoting] Error: java.lang.RuntimeException: Could not convert value while unmarshaling
at org.jboss.seam.remoting.wrapper.BeanWrapper.setBeanProperty(BeanWrapper.java:243) [:3.0.0-SNAPSHOT]
at org.jboss.seam.remoting.model.ModelHandler.processApplyRequest(ModelHandler.java:285) [:3.0.0-SNAPSHOT]
at org.jboss.seam.remoting.model.ModelHandler.handle(ModelHandler.java:91) [:3.0.0-SNAPSHOT]
at org.jboss.seam.remoting.Remoting.service(Remoting.java:297) [:3.0.0-SNAPSHOT]
at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [:1.0.0.Final]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:324) [:6.0.0.Final]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]
at org.jboss.weld.servlet.ConversationPropagationFilter.doFilter(ConversationPropagationFilter.java:67) [:6.0.0.Final]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:274) [:6.0.0.Final]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [:6.0.0.Final]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) [:6.0.0.Final]
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:181) [:6.0.0.Final]
at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.event(CatalinaContext.java:285) [:1.1.0.Final]
at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.invoke(CatalinaContext.java:261) [:1.1.0.Final]
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:88) [:6.0.0.Final]
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:100) [:6.0.0.Final]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [:6.0.0.Final]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [:6.0.0.Final]
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) [:6.0.0.Final]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [:6.0.0.Final]
at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:53) [:6.0.0.Final]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [:6.0.0.Final]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [:6.0.0.Final]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:654) [:6.0.0.Final]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) [:6.0.0.Final]
at java.lang.Thread.run(Thread.java:662) [:1.6.0_23]
Caused by: org.jboss.seam.remoting.wrapper.ConversionException: Date value [NaNNaNNaNNaNNaNNaNNaN] is not in a valid format.
at org.jboss.seam.remoting.wrapper.DateWrapper.convert(DateWrapper.java:61) [:3.0.0-SNAPSHOT]
at org.jboss.seam.remoting.wrapper.BeanWrapper.setBeanProperty(BeanWrapper.java:238) [:3.0.0-SNAPSHOT]
... 26 more

I cannot reproduce the issue using Opera while I can using Firefox. The difference that probably causes the issue is a different date representation. While with Opera I get expected:

Tuesday January 01, 00:00:00 GMT+0100 1901

with Firefox I get

Tue 01 Jan 1901 12:00:00 AM CET

which Seam Remoting is not able to parse back.

Interesting.. I'll look at the date handling in the model example to work out why this is happening.

Resolved by forcing date format of yyyy/mm/dd