So from the letter and reports, Paulson sold, not because he believed the accusations by MW against Sino Forest ( SNOFF / TRE ) were true, but because he felt that even through vindication, the stock price may stay depressed, like ONP, Orient Paper, which he quoted in his letter.
A couple of things to consider though...
Sino Forest has garnered a lot more attention
Sino Forest has had higher volatility, higher volume and trader attention
Sino Forest has a higher short interest
Sino Forest has fallen from a much higher market cap and pps valuation:
>> ONP fell from $9/$8ish to around $4. (around 50% haircut)
>> SNOFF / TRE fell from around $20 to around $2, with a low of around $1.30!!(around 90% haircut)
Seems to me that a vindication for Sino would see a northward correction very unlike ONP.