can you describe what the ALC server is? What is the third-party vendor? Is it exposed via OPC XML-DA standard? If so, you may want to look at PI Interface for OPC XML-DA - Interface Details . Although not programmatic, you may be able to configure it to read from OPC/store in PI, assuming ALC is XML-DA accessible.
To my knowledge, we do not have any out-of-the-box products or interfaces that can be configured to talk to an arbitrary web service. You may need to write your own web service client depending on how ALC exposes its web service. Please provide more details if possible.