Hi, sorry if this is covered, but I couldn't find anything.
I'm contemplating moving a large existing site to 2.5 from 1.5.
I pleased to see that your spent the time making DTRegister 2.5 ready... just wondering if there is a logical and documented upgrade path.
In the readme file found along with the 2.5 version of the component, there is a section labeled "Migration from Joomla 1.5". That will point you in the right direction.