datasource question

Hi
I would preciate any help on calling for a fuction inside a datasource
string using visual basic.

for example:

I have one function that evaluates some condition in each recordset and
would like to create something like this:
mydatacontrol.recordsource = "select * from mytable where
myfunction(variable)='valor'"

the main idea is to replace all the 'Á' by an 'A', the 'é' by an 'e' and

on calling the function

if i use the expression above calling myfunction i get a error
here is my code for myfunction

Public Function myfunction(cadeia As String)
Dim cacentos
Dim sacentos
Dim nciclo As Integer
Dim acento
cacentos = "áéíóúÁÉÍÓÚãõàÕâêîôûÂÊÎÔÛçÇàèìòùÀÈÌÒÙ"
sacentos = "aeiouAEIOUaoAOaeiouAEIOUcCaeiouAEIOU"
For nciclo = 1 To Len(cadeia)
acento = InStr(cacentos, Mid(cadeia, nciclo, 1))
If acento <> 0 Then
cadeia = Left(cadeia, nciclo - 1) & Mid(sacentos, acento, 1) &
Mid(cadeia, nciclo + 1)
End If
Next
myfunction= cadeia
End Function