[BioC] building a new annotation

[Chirag Patel]

Hello,
I would like to build a new annotation using data from the CTD (http://ctd.mdibl.org 
).

This data contains in sqlite DB a main table with the schema:
entrez_gene_id, chemical_id, relation_id, and pubmed_citation_id.

Relation_id is a internal id I use to manage relations between the  
chemical and genes.  Chemical_id is an id used by the CTD to identify  
chemicals.

How may I best do this using the tools available on bioconductor?-- I  
was thinking of using AnnBuilder or AnnotationDbi, but am unsure if  
this is the right way to go; this is a first time building a package  
or an annotation.

Any help would be much appreciated,

Chirag