Manny,
RMS has built in support for credit cards and pin based debit cards (this started out as credit card only to Citi and evolved into credit and debit to any acquirer that can accept Vital format). There is some confusion because some of the processors don't support the mechanism that RMS uses for pin based debit. So whoever you are choosing as a processor, make sure they support credit and debit on RMS. If they really don't know if they do or don't, you're going to suffer trying to get RMS set up correctly.
To answer the question on tips in RMS: In order to change the feature set of card processing in RMS, you have to bypass the built in processing mechanism. We have in the past used a system that did this. But this approach is intrusive. You need to install software, make your own receipts and make many changes in RMS to get the software activated at the right times. It works, but it is installation and setup intensive and hard to support. The built in mechanism works well, is supported by MS and is very easy to install. It would be much better if MS added support for tips, additional pin pads, etc. Unfortunately, they haven't yet.
Marc