HstSiteMenuConfigurationService breaks on custom node type extending hst:sitemenuitem

I get a lot of errors like the following (in a project upgraded from 7.4 to 7.5):

2012-04-12 08:56:20,758 890729916@qtp-1793467229-0 ERROR org.hippoecm.hst.configuration.sitemenu.HstSiteMenuConfigurationService - Skipping siteMenuItem
'/hst:hst/hst:configurations/ns/hst:sitemenus/foo/bar' because not of type 'hst:sitemenuitem'

This is because the project defines a custom node type for sitemenuitems (extending hst:sitemenuitem). In HstSiteMenuConfigurationService, there is a check if the node type of a sitemenuitem equals
hst:sitemenuitem:

if(HstNodeTypes.NODETYPE_HST_SITEMENUITEM.equals(siteMenuItem.getNodeTypeName()))
{
// some code
} else {
log.error("Skipping siteMenuItem '{}' because not of type '{}'", siteMenuItem.getValueProvider().getPath(), HstNodeTypes.NODETYPE_HST_SITEMENUITEM);
}

This breaks the site navigation in the project.