The answer to this question, as already a bit stated by user784227, is depending partially on what the "other" side needs and what the options are. You could for example think about using a service bus like solution to intergrate the two. However, as stated, it depends completly on what is needed and what are the options on both sides.
Sorry to say,.... at this moment we do not have that much to go on based upon the information you provided.
If you have more information please do post it here, or if you have a solution implemented,..... please do share. :-)