Salesforce Metadata Api get Folder sharedTo

Salesforce Metadata Api get Folder sharedTo

I'm trying to use the Salesforce Metadata api to get the sharedTo Field
for folders. SharedTo should be something like this:
http://www.salesforce.com/us/developer/docs/api_meta/Content/meta_sharedto.htm
The folder metadata should contain these fields:
http://www.salesforce.com/us/developer/docs/api_meta/Content/meta_folder.htm
At the moment, its getting only these: AccessType,Name and PublicFolderAccess
I believe this is because I might need to add a request for the sharedTo
Field to the package that i send in packagerequest. However, I dont know
what/how.
This is the code to build the Package:
List<PackageTypeMembers> pd = new ArrayList<PackageTypeMembers>();
List<String> members = new ArrayList<String>();
members.add("sampleFolder");
PackageTypeMembers pdi = new PackageTypeMembers();
pdi.setName("Document");
pdi.setMembers(members.toArray(new String[1]));
pd.add(pdi);
Package r = new Package();
r.setTypes(pd.toArray(new PackageTypeMembers[1]));
r.setVersion(28.0 + "");
Can someone help me? The folder I'm using is public so it should contain
sharedTo.
Thanks!