Since everything in the Windows Azure Platform is managed through a REST Services, you just need a reliable REST library for C++ to perform what you need.
You can have a look at this and that questions for C++ REST library.
Then you can revice the Azure Storage Services REST API Reference for more details on what you want to achieve.
Hope this helps!
EDIT
Just looked the the POCO libraries, noted they have HTTPRequest and HTTPResponse classes. They, along with X509Certificate should be enough to make a valid REST call to Azure management service.