It is still credit -- although the balance has to be paid each month you are still 'borrowing' the money between spending it and paying it back, and, basically, spending what you do not have in your pocket at the time. There may be some circumstances where such cards are allowed, but you would need to discuss this with your IVA provider.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk