[solved] how to avoid incoming SMS to disturb HTTP transfers?

hi,
my application uses a SIM900 module on a Mega2560 board.
The software is designed to receive phone calls and SMS, and to transfer some data to a server.

The data transfers to the server are protected against disturbance from incoming phone calls by setting the GSM to busy mode before starting the data transfer and not busy mode after the transfer.
But setting the busy mode does not block incoming SMS.

What can I do to block incoming SMS until a data transfer to the server is finished?

Solved, see: avoid unsolicited result codes to disturb HTTP transfer - Arduino GSM Shield - Arduino Forum