I'm trying to run an .exe from mIRC with appended arguments, one of them requiring quotes. In simple form:

/run cmd /C "C:\Program Files\....exe" -U "string"

However, when I do this I get an error in command prompt which tells me it's trying to run "C:\Program". So mIRC's either ignoring the first quote or pairing up the second and third for some reason. It works perfectly fine from command prompt itself or without the additional string quotes (and thus the argument).
I tried $qt() and $chr(34), but both these methods do not work. For obvious reasons, I'd say.
So is there a way around this? Is it simply not possible two use two sets of quotes in the /run command or it is a bug?