>> the idea that i have in mind is that when i enter 19600 and the search begins it refresh the locator content to 0000019600, using contains as you say it works fine but don't complete the locator content as i would like
A locator doesn't access the file to find out if it's right or not. So it's not going to change because there's no way for it to know that you're trying to "exact match" a record.
It sounds to me like what you want to use is an Entry field, with a Auto-Complete set. You could easily create a form, with such a field, and a browse, and then use the entry field to filter the browse. Let me know if you need tips for this.
Regarding customised Locator text - your best bet is to right-click / source then search for the calls to CreateLocator, and in the embed before that set loc:SortHeader. Not there may be more than one place where CreateLocator is called, depending on your locator settings.
cheers
Bruce
Cheers
Bruce