Azure copy blob to another account: invalid blob type - azure

Question

I want to copy a 12GB page blob from one storage account to another. At the moment, both sides are "public container". But it doesn't work: HTTP/1.1 409 The blob type is invalid for this operation.
Copying it the same way but within the same storage account works without errors.
What am I missing?
Thanks!
//EDIT: This is how I'm trying to copy blob.dat from account1 to account2 (casablanca lib):
http_client client(L"https://account2.blob.core.windows.net");
http_request request(methods::PUT);
request.headers().add(L"Authorization", L"SharedKey account2:*************************************");
request.headers().add(L"x-ms-copy-source", L"http://account1.blob.core.windows.net/dir/blob.dat");
request.headers().add(L"x-ms-date", L"Sat, 23 Nov 2013 16:50:00 GMT"); // I'm keeping this updated
request.headers().add(L"x-ms-version", L"2012-02-12");
request.set_request_uri(L"/dir/blob.dat");
auto ret = client.request(request).then([](http_response response)
{
std::wcout << response.status_code() << std::endl << response.to_string() << std::endl;
});
The storage accounts were created a few days ago, so no restrictions apply.
Also, the destination dir is empty (account2 /dir/blob.dat is not existing).
//EDIT2:
I did more testing and found out this: Uploading a new page blob (few MB) then copying it to another storage account worked!
Then I tried to rename the 12GB page blob which I wasn't able to copy (renamed from mydisk.vhd to test.dat) and suddenly the copy to another storage worked as well!
But the next problem is: After renaming the test.dat back to mydisk.vhd in the destination storage account, I cannot create a disk from it (error like "not a valid vhd file"). But the copy is already done (x-ms-copy-status: success).
What could be the problem now?
(Oh I forgot: the source mydisk.vhd lease status was "unlocked" before copying)
//EDIT3:
Well, it seems that the problem has solved itself... even with the original mydisk.vhd I wasn't able to create a disk again (invalid vhd). I don't know why as I didnt alter it, but I created it on the xbox one launch day, it was all quite slow so maybe something went wrong there. Now, as I created a new VM, I can copy the .vhd over to another storage without problems (after deleting the disk).

Answer 1

I would suggest using AzCopy - Cross Account Copy Blob.
Check it out here:
http://blogs.msdn.com/b/windowsazurestorage/archive/2013/04/01/azcopy-using-cross-account-copy-blob.aspx