Hi Michael,
Hope you are doing good.
You have really described the issue in detail 
. This is a known issue, please see note
1679822 - Create business system error CIM_ERR_ALREADY_EXISTS: Instance already exists
Anyways, you do not need to use this, just use /nRZ70 Tcode on the abap end. Add the SLD server details in the /n RZ70 TCode in the ABAP server and then retrigger the sld transfer.
Below is the link for this setting:
<http://help.sap.com/saphelp_nw04s/helpdata/en/e7/01503ede925441e10000000a114084/content.htm>
Thank you and have a nice day :).
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Kind Regards,
Hemanth
SAP AGS