If you decide to not use the toolbar we provide please open unit WPCtrRich.PAS and check out method OnToolBarIconSelection.
This method is executed for all toolbar button clicks and WPTools actions. You can see how things are done. You can also call this method from "outside".
When you add standard wptools dialogs to your project, i.e. TWPSearchReplaceDlg You only need to link those to a component of the class TWPDialogCollection.
Add a reference to the TWPDialogCollection instance to the TWPRichText in property WPDialogCollection and the editor can automatically use the dialogs.