Hi!
I must say I have been much more successful in having students use their lexical books, hurray.
It has all depended on an opportunity I have given them to NOTICE how they benefit from the lexical book. I have complimented them on sophisticated outcomes in which new chunks and vocabulary were used and also recorded their outcomes on the flipchart (spoken). Also have I given examples of chunks and language throughout the lesson to simplify the usage of lexical book. Instead of  being reluctant to use their lexical books it has become a MOTIVATIONAL factor due to the fact that they have been able to see the benefits of their lexical books. This is a good example of noticing an issue, reflecting, adapting and analyzing the results.
Well, I am on the road of action research, really.
Juliette Gaasenbeek