How to define a custom portlet css file using the <portlet-skin> element in EPP 5 and 6?

Issue

• We followed the EPP 5 docs, Chapter 2.7.3, to define a portlet specific css file:

http://docs.redhat.com/docs/en-US/JBoss_Enterprise_Portal_Platform/5.1/html/Reference_Guide/sect-Reference_Guide-Creating_New_Skins-How_to_Create_New_Portlet_Skins.html

But EPP 5 creates a non-working CSS-link in html-src-code with the following configuration:

gatein-resources.xml:

    <portlet-skin>
            <application-name>custom</application-name>
            <portlet-name>test</portlet-name>
            <skin-name>Default</skin-name>
            <css-path>/css/main.css</css-path>
    </portlet-skin>

causes portal to create following HTML-code:

    <link id="custom_test" rel="stylesheet" type="text/css" href= "/custom/css/main-lt.css" />

This HTML-link does not contain CSS-file (but some error HTML instead).

For JPP-6.x the guide is at https://access.redhat.com/site/documentation/en-US/Red_Hat_JBoss_Portal/6.0/html-single/Reference_Guide/index.html#sect-Reference_Guide-Creating_New_Skins-How_to_Create_New_Portlet_Skins