configurable location-prefix when use local DTD

We start using X-Men as our standard XML editor in
eclipse. Since we work with a company-wide local DTD
cache, which basically is a well defined directory
containing all relevant DTD files, we would appreciate
if the mapping URL-DTD-->local DTD offers some degree
of parametrization. Today only the DTD filename with a
leading '/' is used. It might be already of great help,
if one can configure a prefixed local path. Thus, the
mapping would look like followed, e.g.:

Configured DTD path prefix: /opt/doc/xml/dtd-cache

URL-DTD: http://java.sun.com/dtd/web-app_2_3.dtd
is mapped to:
local DTD: /opt/doc/xml/dtd-cache/web-app_2_3.dtd

Regards,

-- TOM.