[Zope] SiteAccess smashes 'REQUEST.resolve_url(...)' in DTML ?

Hello, i have some strange problmes by using the "REQUEST.resolve_url('http://mydomain/...')" in DTML if SiteAccess is active. I have also some Sites in use without SiteAccess and no problems with the above method. Has anybody an idea or a 'workaround' for this ? Martin