Actually, I did see that it was supposed to be possible but the following code does not prevent the right and left wheel motors from spinning. I do not have attach statements anywhere else in the code so I am not sure what the issue is.
void setup()
{
rightMotor.writeMicroseconds(1390);
rightMotor.attach(6); //signal wire on right countinuous rotation "drive" servo connected to this arduino pin
rightMotor.writeMicroseconds(1390);
leftMotor.writeMicroseconds(1400);
leftMotor.attach(7); //signal wire on left continuous rotation "drive servo connected to this arduino pin
leftMotor.writeMicroseconds(1400);
panMotor.attach(5); //signal wire on pan servo for ping sensor connected to this arduino pin
panMotor.write(pos); //set PING))) pan to center "90 by default"
Serial.begin(9600);
}