Well, I read alot about DCX but since ever it just crashes mirc at the first access, I was told and I have read that the cause is my os (windows 98), I bought once XP but threw it off after some months of daily crap and annoyancy, and also hardware which didnt have a driver planned for it. So sadly, it's not an option here.

Besides that, having to use a numerous features-dll, which is also quite complex and needs alot learning, even for a first 'hello world' style thing, sounds as alot work for just a narrow goal, also requiring a complete dialog code rewrite, which is not quite an option for a script in a later stage.

I do not know how mIRC handles control id's internally, i.e., if the used OS functions also use them directly or after some mathematical conversion, but maybe a mapping table format "script name:os name" or so could then convert the script 'names' to the format it uses and vice versa.
It would be a major improvement due to the earlier mentioned benefits.