Here is how the data files contained in this package were produced:

1) Download the following files (total size is 41M)
     dmel-2L-chromosome-r5.1.fasta.gz
     dmel-2R-chromosome-r5.1.fasta.gz
     dmel-3L-chromosome-r5.1.fasta.gz
     dmel-3R-chromosome-r5.1.fasta.gz
     dmel-4-chromosome-r5.1.fasta.gz
     dmel-X-chromosome-r5.1.fasta.gz
     dmel-U-chromosome-r5.1.fasta.gz
     dmel-dmel_mitochondrion_genome-chromosome-r5.1.fasta.gz
     dmel-2LHet-chromosome-r5.1.fasta.gz
     dmel-2RHet-chromosome-r5.1.fasta.gz
     dmel-3LHet-chromosome-r5.1.fasta.gz
     dmel-3RHet-chromosome-r5.1.fasta.gz
     dmel-XHet-chromosome-r5.1.fasta.gz
     dmel-YHet-chromosome-r5.1.fasta.gz
   from
     ftp://flybase.net/genomes/Drosophila_melanogaster/dmel_r5.1/fasta/
   and extract in the DOWNLOAD dir.

2) Shell commands:

   for i in `ls *.gz` ; do gunzip $i ; done
   R CMD INSTALL BSgenome.Dmelanogaster.FlyBase.r51

3) R commands:

   library(BSgenome.Dmelanogaster.FlyBase.r51)
   buildDataFiles("DOWNLOAD", "DATA", seqnames(Dmelanogaster), "dmel-", "-chromosome-r5.1.fasta")

