No
Replace Boost( id ) with Boost( iKnife ), where iKnife is the entity index of the knife, then use private offset m_pPlayer to retrieve player id, and add velocity to him (you may also check if it's the first push of attack2)
This may help you :
http://cs-sdk.googlecode.com/svn/trunk/wpn_knife.cpp
Also, you shoule make some research on hamsandwich, fakemeta, on how to use ham hooks and pdatas, before you start anything, else you will make lots of errors and you gonna loose lot of time.
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