You can adjust the sensitivity for the light sensor in the Central Electronics Module. (Second Module BYTE 1)

There are preset values set by VCDS for the various tints available, the GTI is set to HEX 30.
You should be able to set this value from HEX 0 to HEX 64 (100%)
I think that the higher the value the later the lights should come on, haven't tried experimenting with it.