004FB8D0 <-- address
8B 91 <--opcode MOVE EDX
98 02 <--[ECX+298]


You need to find out what the address of ECX is, and add it to the address table the same way as your first example.

Since i dont know how you came to finding that address, i cant really help to explain how you find the address of ECX, but usually, if its something which is displayed after you use "find out what accesses this address" then you just select it, and press "more info" and it will tell you the value of ECX.

Then you scan for that value, making sure you tick the hex box, and a result should appear, add that address to the address table, and then change it to a pointer and add the offset 298