CMIS XPath query error: literal is not supported in the primary path expression; therefore '1' is not valid

Dear Modeshape team,

we figured out following error by using of CMIS queries with Modeshape:

• Create a folder with a literal as name (e.g.: '1')
• Create sub-folder in this folder (e.g.: 'subfolder')
• Create a document in this subfolder
• Execute following CMiS query to search for the document
  SELECT * FROM cmis:document WHERE IN_FOLDER (<OBJECT ID OF THE SUB FOLDER>)

As result following exception is thrown:
The xpath query "/jcr:root/1/subfolder/element(*,nt:file)[(@jcr:mixinTypes = 'mix:simpleVersionable')]" has one or more errors: A literal is not supported in the primary path expression; therefore '1' is not valid

The problem is, that I don't even have a chance to escape something, as the path is generated by Modeshape api (I just provide the object id of the sub folder).

Best regards
Vitali