The generator matrix

 1  0  1  1  1  X  1  1  1  1  0  X
 0  1  1  X X+1  1  0 X+1  X  1  1  1
 0  0  X  0  X  0  X  0  X  0  X  X

generates a code of length 12 over Z2[X]/(X^2) who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+28x^12+3x^16

The gray image is a linear code over GF(2) with n=24, k=5 and d=12.
As d=12 is an upper bound for linear (24,5,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 5.
This code was found by Heurico 1.16 in 0.000329 seconds.