[Vtigercrm-developers] Function Overriding?

[Alan Lord]

Is there a "proper" way to override a core vtiger function?

Example: I have some custom fields added to a Quote & Invoice that I 
would like to carry over to the Invoice.

It is fairly straightforward to edit and modify the 
getConvertQuoteToInvoice() function in include/utils/EditViewUtils.php 
but clearly this isn't the best way to maintain compatibility through 
upgrades etc...

What do others do in this kind of situation?

Cheers

Al