Are you trying to transfer a file FROM Alfresco INTO IBM Content Manager via CMIS? Then unfortunately I have to tell you that Alfresco ECM does not (yet) provide the means to integrate with other CMIS repositories in terms of out-of-the-box functionality. You would have to create an addon to Alfresco to support Alfresco connecting to other repositories and transfering node contents to them.
Alfresco BPM - as far as I know - supports CMIS client operations (accessing / updating / transfering) on CMIS repositories. These are typically used to access items in Alfresco ECM but I would expect they work with other CMIS compliant repositories as well.
If the question has no relation to any Alfresco product at all then this platform might not be the right place for it.
