how to specify extension features in response to OPTIONS request

Hi,

is it possible to specify extension features (that are not defined in the
DeltaV spec) in the response to a OPTIONS request ?

We want to use this kind of extension to allow usage of our client against
our server (which 
will support some extensions which are not in the standard) but it should
also work against
other servers which clearly will not have these extensions. Therefore we
need some mechanism
to find out which extension features are supported by a given server. Some
namespace mechanism could be used to prevent name clashes between extension
features defined by different servers. E.g. our extension could be named
SAP:ourSpecialExtension.

regards
Matthias