String replacement by OUString queries

Hi all,

I am trying to replace String -> OUString, but am stuck badly at certain
places.

I replaced:

'rName.SetChar( i, c )' by the following:

                OUStringBuffer aTmpStr( rName.getStr() ) ;
                aTmpStr[ i ] = c ;
                rName = aTmpStr.makeStringAndClear() ;

But I get an error: ‘OUStringBuffer’ was not declared in this scope !
I tried out many things but with fail.

Secondly, I would like to know that what are the parameters to replace
foo.Erase(a,b) i.e. the middle part of some string using OUStringBuffer()
or copy ?

I would be more than happy if someone could help me in this regard.
Waiting for an earliest reply!

Thanks

Prashant Pandey