Dear Ed, in the past we have successfully searched in an electron density map (computed in the whole cell) with Molrep.
If you have a second crystal form and you can cut the density of the monomer off, Phaser also gives very good results when searching with that electron density - after that your maps can be improved with dmmulti cross-crystal averaging. Good luck! Pietro -- Pietro Roversi EP Abraham Fellow in Biochemistry - Lincoln College - Oxford Sir William Dunn School of Pathology, Oxford University South Parks Road, Oxford OX1 3RE, England UK Tel. 0044-1865-275385