Peoplesoft Document based REST services -- How to catch Schema errors

Hi All

Our Client is using a third party tool to send XML via a REST based service.

The XML has around 100 elements in 6 nodes

If the 60th element(in node 2) is too long (than the schema), our Integration broker fails saying that "100th element(in node 4) is wrong"..

But when I try this XML in the PostMan, I get the correct error  (i.e. 60th element is wrong)..

Any ideas, on what needs to be done with the Configuration, to display the correct error?

thanks in advance

Rahul