Looking for guidance with FTP from SD Card to server via SIM900

Hello all. I have a logger that stores data to the micro SD card just fine. I have it set up in a fashion that if it is a new day, it creates a new log file on the card with the current date as the file name. Upon creation of the new days file, I'd like to send the previous day off the my web server via FTP using my SIM900 modem.

I have seen SurferTim's example at: Arduino Playground - FTP but I don't think that will allow me to use the cellular modem. Also, I should mention that the log files can be as large as 300Kb. Is there a way to do this just using AT commands? I don't see how with such a large file.

Can I get some ideas to try to get this accomplished?