Tamiya Bruiser front stervo problems

[FoxShot 280]

I fitted the Shapeways front servo mount to my Bruiser, and I am seriously unhappy with the steering action.

 

Due to the Ackerman principle (i think) I am getting considerably more turn angle in one direction than the other. 

When I first did it, it was so bad that it bent the standard metal plate ta the ball joint goes onto. (Part BA35, Section 9 in the instructions).

i am guessing that the white plastic L piece counteracts this. 

Is there a way round the problem as my Transmitter is the Futaba T4YF, and doesn't have end point adjustment. 

Its REALLY winding me up. Just want to use the thing again! Its all muddy and wet here

 

If you need pictures, I can take some.