how to change pin assignments in SoftSerial

So, thanks to boguz, I found the libraries. Now I need to change the tx and rx pin assignments to match the SeeedStudio board.
The board uses pins 7 and 8.
I found the following in GSM3SoftSerial.cpp:

#if defined(AVR_ATmega328P)
#define TXPIN 3
#define RXPIN 2
#define RXINT 3
#elif defined(AVR_ATmega2560) || defined(AVR_ATmega1280)
#define TXPIN 3
#define RXPIN 10
#define RXINT 4
#elif defined(AVR_ATmega32U4)
#define TXPIN 3
#define RXPIN 8
#define RXINT 3
#endif

So this looks like a place to set the tx and rx pins, but it looks like it depends on something #defined somewhere else.
How do I figure out where that is?

Brad

So this looks like a place to set the tx and rx pins, but it looks like it depends on something #defined somewhere else.
How do I figure out where that is?

Those are set when you select a board from the Tools + Board menu.

I see that, but there is nowhere to say which GPRS board you are using, and the SeeedStudio board uses different tx/rx pins than the libraries are expecting. I'm guessing that pins 7 and 8 used to be the defaults for SoftwareSerial, but they no longer are, and that's where the GPRS board is looking for inputs, so it doesn't see anything coming in.
Keep in mind that this is all new to me, and I may be completely confused.

I'm guessing that pins 7 and 8 used to be the defaults for SoftwareSerial, but they no longer are, and that's where the GPRS board is looking for inputs, so it doesn't see anything coming in

Surely one of the reasons for using SoftwareSerial is that you can define the Tx and Rx pins used when creating the serial instance, and that they are not hard coded. There are, however, some limitations on which pins can be used depending on the Arduino board being used. Which board are you using ?

I have two UNO boards, an early one, and an r3
I tried hardwiring the SeeedStudio shield to the r3 instead of stacking it, but I'm not sure which pins SoftSerial is using as tx/rx.
I tried 2 and 3, but no luck. I'm not sure if those are the wrong pins or if there is something else I'm not thinking of.
Thanks for your help. I'm just getting started with this, and it is difficult following how all the libraries interact.

Post the code that you are trying to use. What pins are defined in the SoftwareSerial setup, the equilvalent of this line ?

SoftwareSerial mySerial(10, 11); // RX, TX