How to add a function to an activex component?

I stole an activex component that I am tying to moodify
so that I can build an ocx component to be slammed into
my C++ code.

Function

private Sub UserControl_InitProperties()

was already there.

When I tried to add (Declarations area of the UserControl)

public Sub UserControl_Initialize(FileName as string, _
DirFullPath as string, TBD as string)

So that I can call it (UserControl_Initialize) in my C++
code and pass in info, I get a compile error

"Procedure declaration does not match description of event
or procedure having the same name"

What I am I doing wrong?

'Initialize Properties for User Control
private Sub UserControl_InitProperties()
set Font = Ambient.Font
End Sub

' added to be exposed in c++ code and pass in values
public Sub UserControl_Initialize(FileName as string, _
DirFullPath as string, TBD as string)
'public Sub UserControl_Initialize()

Dim sFile as string
Dim tFile as string

' MsgBox "Filepath='" & sFile & "'" & vbCr & "FileTitle='" & tFile & "'"

Call startWord(sFile, tFile)

End Sub