The string hasOfferCatalog is not a registered keyword

Hello, i validated today my XHTML Page that use RDFA 1.1 with schema.org
vocabulary and i have this error :

Bad value hasOfferCatalog for attribute rel on XHTML element a: The
string hasOfferCatalog is not a registered keyword.

The RDFA 1.1 Core specification says : "For example, in (X)HTML there is
no clear way to add new @rel values; RDFa sets out to explicitly solve
this problem, and does so by allowing IRIs as values" and "rel :
a white space separated list of TERMorCURIEorAbsIRIs, used for
expressing relationships between two resources ('predicates' in RDF
terminology);

The validator says : "Info: Using the preset for XHTML with SVG 1.1,
MathML 3.0, RDFa 1.1, and ITS 2.0 support based on the root namespace."

Please it's possible to fix this ?  Thanks you. :)