orion-ld: create subscription with URL including Bearer Token in the header

Hello FiWare specialists, I like to create a subscription, which pushes notifications to an external service. The external service needs authorization with a barrier token. If I use curl, I add "--header 'Authorization: Bearer XXX'". How can I add a barrier token to the subscription request?

"notification": {
    "attributes": [ "id", "type", "name", "location", "occupancy"],
    "format": "normalized",
    "endpoint": { 
        "uri": "http://a.b.c.de:1111", 
        "accept": "application/json"
    }
  },

Is there an option to add a header field to the "endpoint" setup in the subscription like:

"headers": "Authorization: Bearer XXX"

Hopefully, you can help me in that case. Thanks, Knigge