SainSmart 20 x 4 LCD wanting to use I2C from Arduino Uno

Hey Guys.
Firstly: Thanks for all the great info about the SainSmart LCD2004.
I got it working following Andrews advice.

But now I have a problem:

I'm trying to use the Wireless SD Shield:

w/ the Serial LCD described in this topic.

I can get the LCD to work, but not the SD.
fm says:
"Just create two objects (variables) initialising them correctly and they will work. "

can anyone please explain that to me?
The only wires coming off the LCD2004 are:

GND
VCC
SDA
SCL

and I currently have them wired:

GND - arduino GND
VCC - arduino 5V
SDA - arduino A4
SCL - arduino A5

also the Wireless SD shield uses pin 4 as the SDCS (chip-select).

Any help is appreciated.
Thanks!