replace руками можно сделать:

alter function "dba".replace(in @Src_Line varchar(20),in @from varchar(20),in @to varchar(20))
returns varchar(20)
begin
declare ret_line varchar(20);
declare pos integer;
set pos=charindex(@from,@Src_Line); //find start pos
if pos=1 then
set ret_line=@Src_Line
else
set ret_line=substring(@Src_Line,1,pos-1)||@to||substring(@Src_Line,pos+length(@from),length(@Src_Line)-(pos+length(@from)-1))
end if
;
return(ret_line)
end