How can you tell that WinCC has received data from AR_SEND (SFB37)?
If the data has been sent successfully to WinCC, the parameter "DONE" of the AR_SEND block is set to "1". In WinCC there is no way of checking whether the data has been stored successfully in the archive.
If the data has its own time stamp in AR_SEND, it is also stored chronologically in WinCC. Detailed information on parameterizing the AR_SEND block is available in the WinCC Information System (WinCC Online Help) under the keyword "AR_SEND: Data Block Structures - Structures and Parameters". Note the examples given there.