Digital Cable SPDIF/COAX to AES/EBU Balanced?

I have a new DAC coming that only accepts balanced digital inputs vs. coax/spdif inputs. Can anybody tell me if a standard RCA to XLR adapter would work for this (so I can continue to use my existing digital cable) or do I need to have a custom cable made?

I was instructed by EMM Labs that the cable can be either 75 or 110 Ohm for this application.

Thanks for any input.
Ck - this is, I believe, a definite problem. AES/EBU digital transmission specs call for 110 Ohms and SPDIF calls for 75 Ohms - so what company is going to make you an upconverting 75 Ohm to 110 digital cable and how could they possibly do that? Using an adapter might "function", but will certainly NOT get the performance you paid for from the EMM DAC. To my knowledge and in my experience, you are in need of a transport with AES/EBU out or a DAC with SPDIF in for this to work properly. Talk to Steve Huntley at Great Northern Sound - he's the digital guru that can advise you with absolute certainty. Good Luck!
Thanks for the reply JWP. I currently have an Opus 21 with the GNSC mods that I bought from Steve, he is a great guy. According to DH Labs, they reported to me the following:

DH Labs D-75 rca to BNC and put a 75ohm to 110ohm adapter on it. This is a true 75 to 110ohm conversion.

I will of course be using a EMM Labs transport, but also want to be able to feed a digital signal from my hard drive based system to the DAC. I typically use the HDD system for background music only anyway, so if I give up a slight amount in quality, that is okay as long as it is better than using the internal DAC in my HDD system.

Of course the idea situation would be to have an HDD system that I could sync the clock to the EMM labs DAC, but this is not going to happen with my existing equipment nor am I willing to spend thousands for the HDD system upgrade to be used as purely background music.

I am still a bit concerned as to how this will work from a quality perspective of sound, but guess since the cable is pretty inexpensive, I am not going to be out very much. I should be able to do a fairly easy side by side comparison between the HDD's internal DAC and the digital out to the EMM labs by simply switching inputs on my preamp.