You need vcds to do this

VCDS can be used to set the speed limit at which the TV will go off and receive the warning in the MMI, The default is ussually set between 4 and 7 MPH, you will also need to unlock the security using vcds, a code generator and full instuctions are in the links below

for the D3 model with MMI 2Gl      for the D3 Model with  MMI 3G