C-CDA Unknown Code for Code System in procedures

Question

When a system is populating a C-CDA, and they are not storing the code for the code system, what is the proper way insert it into the document?

For example, in procedures the CPT4 code was not known, so they inserted the following:

{  "name": "--",  "code": "--",  "code_system": "2.16.840.1.113883.6.12",  "specimen": {    "name": null,    "code": null,    "code_system": null  },  "performer": {    "street": [],    "city": null,    "state": null,    "zip": null,    "country": null,    "organization": null,    "phone": null  },  "device": {    "name": null,    "code": null,    "code_system": null  },  "date": "08/28/2014”}

or xml

<entry typeCode="DRIV">
<procedure classCode="PROC" moodCode="EVN">
    <templateId root="2.16.840.1.113883.10.20.22.4.14"/>
    <id root="e401f340-7be2-11db-9fe1-0800200c9a66"/>
    <code code="--" codeSystem="2.16.840.1.113883.6.12" 
        codeSystemName="CPT-4" displayName="--">
        <originalText>
            <reference value="#Procedure0"/>
        </originalText>
    </code>
    <statusCode code="completed"/>
    <effectiveTime>
        <low value="20140828"/>
    </effectiveTime>
</procedure>
</entry>

I see references that possibilities are to mark it as UNK or OTH, but this one really just seems like garbage considering there is no name even.. Should it even be included? and if it should be, like if there was a valid name, shouldn't the code be listed as UNK or OTH then?

Based upon some of the other questions asked regarding C-CDA codes, i didn't see one in that corresponded with my question.

Thanks!