You could probably use URLDeploymentSorter in your conf/jboss-service.xml file and make your jboss-jca.sar file get deployed before anyother services are deployed.
<attribute name="URLComparator">org.jboss.deployment.scanner.PrefixDeploymentSorter</attribute> <attribute name="URLs"> 1.deploy/jboss-jca.sar </attribute>
I don't think using the PrefixDeploymentSorter would be the best way since SAR's are the first to be deployed when using the default DeploymentSorter.
What kind of application (SAR, EAR, JAR....) are you using. Does it work if you move your package from the /deploy folder and back after JBoss started up?
Why can't a SAR be deployed with PrefixDeploymentSorter? I don't see any reason for not employing this technique.
From what you say (or from the comments in jboss-service.xml), it appears that, SARs should get deployed first. But from the exception that's mentioned, it shows that the SARs are not getting deployed. So, that would mean that DeploymentSorter isn't functioning properly.