Calling Stored Procedure using NHibernate as a Named Query with Input Parameters
<hibernate-mapping default-cascade="none" xmlns="urn:nhibernate-mapping-2.2"
assembly="StudentVoiceGroups.Entities" namespace="StudentVoiceGroups.Entities" >
      <sql-query name="CASCADE_POSITIONTEMPLATE_PERMISSIONS" cacheable="false">
        <return class="PositionTemplateUpdateCascadeResult" alias="result">
          <return-property name="UpdatedPositionsCount">
            <return-column name="UpdatedPositionsCount" />
          </return-property>
        </return>
        exec CASCADE_POSITIONTEMPLATE_PERMISSIONS :PositionTemplateId
      </sql-query>
    </hibernate-mapping>

public class PositionTemplateUpdateCascadeResult
{
    public int UpdatedPositionsCount { get; set; }
}

EXEC [CASCADE_POSITIONTEMPLATE_PERMISSIONS]  15

<hibernate-mapping default-cascade="none" xmlns="urn:nhibernate-mapping-2.2"
    assembly="StudentVoiceGroups.Entities" namespace="StudentVoiceGroups.Entities" >
<sql-query name="CASCADE_POSITIONTEMPLATE_PERMISSIONS" cacheable="false">
      exec CASCADE_POSITIONTEMPLATE_PERMISSIONS :PositionTemplateId
</sql-query>
</hibernate-mapping>

<hibernate-mapping default-cascade="none" xmlns="urn:nhibernate-mapping-2.2"
  assembly="StudentVoiceGroups.Entities" namespace="StudentVoiceGroups.Entities" >
  <sql-query name="CASCADE_POSITIONTEMPLATE_PERMISSIONS" cacheable="false">
    <return alias="result" class="YourNamespace.PositionTemplateUpdateCascadeResult, YourNamspaceAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">
        <return-property name="UpdatedPositionsCount" column="UpdatedPositionsCount" />
    </return>
    exec CASCADE_POSITIONTEMPLATE_PERMISSIONS @PositionTemplateId=?
  </sql-query>
</hibernate-mapping>