Pass Param out in Activex

i write a axtivex control . this control has a fuction (Ex: SignData Function) and I want pass Data block which is result of this fuction out as a variant . but i can't do it . please suggest a solution :
detail :

Code:

---

VARIANT_BOOL CCSPACOSACTIVEXCtrl::SignData(VARIANT &DataIn, LONG DataInLenth, VARIANT &DataOut, LONG* DataOutLenth)

{
    BYTE* result;
    ...
    // i want to pass result to DataOut
}

---

from other Application (Dotnet , website with java script code) i Call this function and desire get result data in DataOut variant

So set DataOut to whatever you want to send. What is the issue?

I wan write a function in Activex which following desire

Byte[] signData(Byte[] datain , int len)

datain is array of Byte and Data out is array of Byte too
how to do it ?
thanks you very much