GSM Shield on board RTC

Is it possible to get support for the internal RTC of the GSM modem in the GSM library?
It shouldn't be too hard, querying for the time is a simply AT command 'AT+CCLK?' and setting the time is simply 'AT+CCLK=""'
Because there doesn't seem to be a way to directly send and receive commands from the modem yourself.

I did try this:

char time[20];
theGSM3ShieldV1ModemCore.println("AT+CCLK?");
int timeout = 1000;
int start = millis();
while((millis() - start) < timeout && !theGSM3ShieldV1ModemCore.theBuffer().extractSubstring("+CCLK: \"", "\"", time, 20)) ;

Which seemed to work for the first time only, but not any other time;

Anyone? I've been looking for a solution to this but haven't found one yet. I also tried looking at the source code of the library myself but still can't figure out what I'm doing wrong.