Valuation of a Start-up in a BRIC country

Hello,

On the first I would like to know which is the best method to value a Start-up (DCF, multiples, etc)? How would you do it?

On the other hand I have been struggling to get the best way to value a Marketing Consulting firm (start-up) that is already being profitable in Brazil. I think DCF is a good choice as using multiples is kind of difficult because the firms you would to compare with this start-up would be much larger and results might not be reliable. In the case we stick to the DCF model I am doubting about the Cost of Capital.

1) COST OF EQUITY: I know of the existence of several methods to calculate the Ke in risky markets like the Lessard, Godfrey, Goldman Sachs, I guess those are the most complete ones but also too complicated to apply, what do you think? In my case I used the CAPM model:

a) RISK FREE RATE: I have looked for Brazilian government bond rate from Damadoran's (Proffessor at the NYU) tables:

http://pages.stern.nyu.edu/~%20adamodar/ (Section: Country Default Spreads and Risk Premiums)

But then here there are two different data: Sovereign Rating based Equity Risk Premiums and Sovereign CDS based Equity Risk Premium; which one is the most appropriate?

b) BETA: I have used the advertising unlevered beta from the "Levered and Unlevered Betas by Industry of Emerging Marktets" section of the same website.

c) MRP: Returns from Brazilian stock exchange market - Brazilian government bonds return?

2) COST OF DEBT: I guess it should be composed of the risk-free rate and a credit risk premium, which should the be the Credit risk premium? or it would be better to follow a more simple way adding up all the Interest paid last year and dividing them by the amount of debt outstanding?

Thank you very much for your time!