I am trying to understand the impact of substitution vis-a-vis default in a manged CDO, any help on the below questions will be very helpful.(I am a new to these concepts so will appreciate any links to documents/papers on mechanism of managed CDO's)1. How do I price the net Loss/Gain due to a substitution in the managed synthetic CDO tranche? e.g. if I have a CDO with 100 underlying entities and I replace one of them with spread of 400 by another with spread 20, how is my tranche & MTM affected? 2. How do I calculate the trading losses say the above entity with spread 400 had a spread of 200 at inception of CDO?3. How do I calculate the impact on a tranche if an entity defaults, so say I sell protection (buy CDO tranche) with 100 entities and 1 defaults so then, I make the payment for the defaulted entity but then what is the tranche attachment/dettachment for my CDO with remaining 99 entities.Thanks