Hi Nanda
Having done this a few years ago, I took the approach that the ERP system does not really need to keep all the maintenance items (spare parts, etc) as this requires a lot of data maintenance.
So instead the spares are kept in Maximo - infact we did most things in Maximo - with a few major exceptions. Firstly we we interfaced any Purchase orders generated by maximo so that they were actually processed by JDE. Secondly we interfaced receipts so that RNV records were created in JDE. This then allowed us to pay suppliers from JDe and have a coherent AP system. The final piece of the jigsaw was to create a one-off reversing journal at month end equal to the value of the "spare parts" in Maximo, so that the balance sheet in JDE was correct and the accountants didn't get any surprises
In summary, let Maximo manage what it is good at, but do the payments out of JDE