Step One: How are you connecting an SLC-5/04 controller to Ethernet ? The SLC-5/04 has a Data Highway Plus network port and a DF1 protocol serial port.
I presume you're using a 1761-NET-ENI.
There are two aspects of this that you will have to figure out:
1. Routing. The DF1 port of the SLC-5/04 only allows you to specify a DF1 target node. The routing table in the 1761-Net-ENI allows you to equate this target node with an IP address and a "CIP Path" to navigate to the CompactLogix CPU.
2. Data Table mapping. The DF1 port of the SLC-5/04 only allows you to address SLC or PLC-style data table files, but the CompactLogix uses tag names. In RSLogix 5000 there is a PLC/SLC Data Mapping tool that allows the CompactLogix to respond to PLC/SLC data table requests with data from a tag array.
There are quite a few Knowledgebase documents about this sort of thing. What have you tried doing so far ?