I'm afraid I don't know how they operate with IVA's. Hopefully someone else will be along.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
Most car finance firms have insolvency clauses in their terms, however, not all trigger them. To further muddy the waters some firms do not seem to be consistent with their reactions either.
You will need to check your paperwork for those clauses and then possibly contact the lender.
Be sure to check that the agreement is HP ( so secured on the car) or an unsecured loan, as this will affect how it is treated in an IVA as well as the finance companies powers of repossession.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014