I have qsig from IPO to various systems but not explicitly a realtis.
you will need shortcodes to dial out on the qsig link to call the realtis, these shortcodes will need to perform any manipulations to digits sent to the realtis
calls received from the realtis will be treated as if they were dialed directly on switch, this is where line shortcodes can come in useful for reprocessing then received digits
A Maintenance contract is essential, not a Luxury.
Do things on the cheap & it will cost you dear