Software serial - doesn't support parity / stop bit selection?

I am using the Software Serial library to utilise D) - D7 pins as TX, RX for RS232 connectivity.

While this works ok for the main hardware RX,TX pins:

Serial.begin(2400,SERIAL_8N1);

This will not compile for my use of other pins

mySerial.begin(2400,SERIAL_8E1);

error message is:

Arduino: 1.6.5 Hourly Build 2015/06/05 07:12 (Mac OS X), Board: "Arduino Duemilanove or Diecimila, ATmega328"

MBusReader.ino: In function 'void setup()':
MBusReader:22: error: no matching function for call to 'SoftwareSerial::begin(int, int)'
MBusReader.ino:22:31: note: candidate is:
In file included from MBusReader.ino:3:0:
/Applications/Arduino.app/Contents/Java/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h:92:8: note: void SoftwareSerial::begin(long int)
void begin(long speed);
^
/Applications/Arduino.app/Contents/Java/hardware/arduino/avr/libraries/SoftwareSerial/SoftwareSerial.h:92:8: note: candidate expects 1 argument, 2 provided
no matching function for call to 'SoftwareSerial::begin(int, int)'

This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.

Doesn't want two arguments - not sure why mySerial.begin doesn't inherit this from Serial.begin ?

I am using the Software Serial library to utilise D) - D7 pins as TX, RX

Which pin is D)?

This will not compile for my use of other pins

mySerial.begin(2400,SERIAL_8E1);

Of course not. But, since the Arduino, in hardware or software serial, does nothing about parity (errors), the parity setting doesn't matter.

not sure why mySerial.begin doesn't inherit this from Serial.begin ?

Why should SoftwareSerial inherit from HardwareSerial? The two classes are completely different.

Use a Mega with 4 hardware serial ports.