Late Loading of remote Data (RestKit and CoreData) - ios

Question

I'm working a long time on this problem, but couldn't find a solution
that fits my needs.
The problem is, how could I load data and map them to the relationship
without loading the whole structure
Simple example:
We got some birds:
{
"birds":[{
"bird":{"id":"1","value":"LaLeLu"},
"bird":{"id":"2","value":"LeLeLa"},
...
}]
}
This could get mapped by something like this:
RKManagedObjectMapping *birdMapping = [RKManagedObjectMapping
mappingForClass:[Bird class]];
menuMapping.primaryKeyAttribute = #"identifier";
[menuMapping mapKeyPath:#"value" toAttribute:#"value"];
[menuMapping mapKeyPath:#"id" toAttribute:#"identifier"];
[[[RKObjectManager sharedManager] mappingProvider]
setMappingForKeyPath:"birds.bird"];
Works great by now.
Now every bird could have a lot of comments - but I don't wanne load
all these comments with the first request.
Comments should get loaded when users clicks the specific bird.
So I request:
NSString *resourcePath = [NSString stringWithFormat:#"/birds/%#/
comments", myBird.id]
[[RKObjectManager sharedManager]
loadObjectsAtResourcePath:resourcePath];
I could change the response that it fits the needs of RestKit - but
what are the needs?
{
"comments":[{
"comment"{"id":"1","value":"Comment1","bird_id":"1"}
}]
}
And now I don't have an idea how to map this response.
Mapping the comments without any relation to the birds is no problem:
RKManagedObjectMapping *commentMapping = [RKManagedObjectMapping
mappingForClass:[Comment class]];
menuMapping.primaryKeyAttribute = #"identifier";
[menuMapping mapKeyPath:#"value" toAttribute:#"value"];
[menuMapping mapKeyPath:#"id" toAttribute:#"identifier"];
[[[RKObjectManager sharedManager] mappingProvider]
setMappingForKeyPath:"comments.comment"];
Hope someone understands my problem and could help

Answer 1

For all who ware interested in the solution:
RestKit 0.10.0 fix the problem:
RKManagedObjectMapping *commentMapping = [RKManagedObjectMapping
mappingForClass:[Comment class]];
commentMapping.primaryKeyAttribute = #"identifier";
[commentMapping mapKeyPath:#"value" toAttribute:#"value"];
[commentMapping mapKeyPath:#"id" toAttribute:#"identifier"];
// Here starts the relevant part:
[commentMapping mapKeyPath:#"bird_id" to Attribute:#"bird_id"];
[commentMapping mapRelationship:#"bird" withMapping:birdMapping];
[commentMapping connectRelationship:#"bird" withObjectPropertyForPrimaryKeyAttribute:"bird_id"]
[[[RKObjectManager sharedManager] mappingProvider]
setMapping:commentMapping ForKeyPath:"comments.comment"];