Excel (vb6 dll) Formula Help & arguments description

Hi.

Im getting closer to finishing my Excell ADDin, BUT, i got stuck on a major problem!!!

1 - How can i define some help for each argument of my formulas?
2- How can i define the description of the formula on the "insert function" wizard?

I´ve tried several ways (XLA to passes parameters to the DLL, almost a winner, BUT an excel addin (XLA) calculates all UDF´s on open... So... no go!)

Can anyone help me?

Thanks a lot
Jorge

P.S: Someone told me that this is only possible in Visual studio/ Xll addin.... C++ ( i couldn't believe it...)