Custom rendering for the PrimeFaces component works fine in Tomcat, but not in Websphere

I am using MyFaces 2.1.9 and PrimeFaces 3.5. I implemented my own renderer for <p:inputText>. This works great at home with Tomcat. But this does not work with Websphere. I set breakpoints in a custom rendering class, but they never fall. I do not see anything in my magazines. However, when I register the same user renderer with standard JSF <h:inputText>, then it works fine.

I registered it in the faces-config.xmlfollowing way:

<render-kit>
    <renderer>
        <component-family>org.primefaces.component</component-family>
        <renderer-type>org.primefaces.component.InputTextRenderer</renderer-type>
        <renderer-class>xxx.xxx.xxx.MyInputRenderer</renderer-class>
    </renderer>
</render-kit>

How can I resolve an error when registering a custom renderer?