My company must have spent 18 months or so investigating how we might satisfactorily operate IPR on BaaN.
One software house - Grosvenor Systems - demonstrated to us a complete software package (Ricardo) for IPR duty management. This system, as I recall, used the X4000 protocol for electronic transfer of data between client and Customs. The system required elaborate interface routines which funnel data out of BaaN into the Duty Management system. Their address is http://www.grosvenor-eu.com
In the end, we went a slightly different route: we purchased some bespoke API software that captures critical non-EU imports at point of goods receipt and writes the records to customised tables in Baan. Interface sessons allow our Tax clerks to update the customized BaaN records with import values, Entry Numbers, commodity codes etc. I then developed a whole suite of Crystal and Infomaker reports to produce the required Customs reports - ie "Diversions to Free Circulation" , "Goods Imminently due to Expire in Next Calendar Month", "Disposal of IPR Goods not Eligible for Article 544" etc. Currently, we submit paper declarations
C&E audited our systems and considered them satisfactory.
Ricardo mentioned above might be your first point of call.