The retrieveAllResourcePropertiesRequest type does not allow mixed content.
There is no restriction on type derivation.
XML Instance
<...>
The network resource logical name. This
name is used to uniquely identify a
network resource specification. Service
implementations may be configured to use
their own network resource logical names
or may share logical names.
<xhtml:p>The network resource logical name. This
name is used to uniquely identify a
network resource specification. Service
implementations may be configured to use
their own network resource logical names
or may share logical names.</xhtml:p>