From the spring documentation, you will see that for org.springframework.web.jsf.el.SpringBeanFacesELResolver:
delegates to the Spring's 'business context' WebApplicationContext
first, then to the default resolver of the underlying JSF
implementation
and for org.springframework.web.jsf.DelegatingVariableResolver:
will first delegate value lookups to the default resolver of the
underlying JSF implementation and then to Spring's 'business context'
WebApplicationContext
As you can see, the behavior is very different. If you don't care about order, you are fine, but if you actually did intend to use org.springframework.web.jsf.el.SpringBeanFacesELResolver then all you have to do is ensure the version of el-api.jar in your dependencies is compatible with your version of spring. For me, I have this (in my maven pom):
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>3.0.5.RELEASE</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>el-api</artifactId>
<version>6.0.32</version>
<type>jar</type>
<scope>provided</scope>
</dependency>