django - Tastypie - Multiform post with foreign fields -

i'm trying post multiform tastypie.

the django model is:

class message(models.model):     recipient = models.foreignkey(user, null=true, related_name='recipient') 

the tastypie resource:

class messageresource(multipartresource, baseresource):      recipient = fields.toonefield(userresource, 'recipient',full=true) 

part of form data:

post /api/message/ http/1.1 host: 127.0.0.1:8286 content-type: multipart/form-data; boundary=boundary+0xabcdefgboundary accept: application/json content-length: 6462 accept-language: en;q=1, fr;q=0.9, de;q=0.8, ja;q=0.7, nl;q=0.6, it;q=0.5 accept-encoding: gzip, deflate connection: keep-alive user-agent: c/1.0 (iphone simulator; ios 6.1; scale/1.00)  --boundary+0xabcdefgboundary content-disposition: form-data; name="fetched"  0 --boundary+0xabcdefgboundary content-disposition: form-data; name="recipient[id]"  2 --boundary+0xabcdefgboundary content-disposition: form-data; name="recipient[username]"  joe --boundary+0xabcdefgboundary content-disposition: form-data; name="text"  test --boundary+0xabcdefgboundary content-disposition: form-data; name="image"; filename="photo.png" content-type: image/png  <binary data> 

since recipient related object, attributes in brackets. tastypie not recognize related object , post fails.

what missing?