Deriving a new component from TCustomMemo

Hello I am new for -Delphi 6-

I need a memo control having the possibility to set the cursor position.
I have seen that the TMemo class has the SetCaretPos method hidden while it
is available in the TCustomMemo class from which it derives.

I am trying to derive a new component from TCustomMemo following the help:
i have created the new component specifing TCustomMemo as anchestror, I have
saved and compiled the unit (without any change for the moment), I have
installed the package but I cannot see the new icon in the component

The strange thing is that if I select the "Configure palette..." in the menu
I can see the new component in the palette properties dialog.

Where is the mistake?

I have derived a new component from the TMenu class and in this case
everything goes OK!
Do I need absolutely change some property in the component derived from
TCustomMenu to have it available in the palette?

Thank you in advance.