The iBATIS documentation is a little sketchy when it comes to dealing with Stored procs. But I am able to execute stored proc via. SQLMaps. Create your sqlMap xml file and setup your proc like this:
<procedure id="getAccounts" resultMap="accounts" parameterClass="com.j2eegeek.ibatistutorial.domain.AccountID">
{call dbname.procname(#acctID#}
</procedure>
The input can be a parameterClass or just a Map.
<parameterMap id="getAccountsCall" class="map">
<parameter property="acctID" jdbcType="INT" javaType="java.lang.Integer" mode="IN"/>
</parameterMap>
Email me directly and I can give you more info. hope this helps.
--Vinny
http://www.j2eegeek.com/blog/