Refreshing bigger dimensions using PROCESS ADD

Hi,I want to refresh my cube. I am using SSIS package, and used SSAS Analysis Task.For Fact table, there is a mode "PROCESS ADD" which actually add data to Fact table.I wanted to do the same to our Bigger Dimensions also. But I don't see the m ode "PROCESS ADD". I have only "PROCESS UPDATE". I read on internet that I can use "PROCESS ADD" using the XMLA code in SSIS package. I need some direction on it and how to do that and how to handle the error if we want to use XMLA code.Is there any way that I can do a incremental load of my bigger dimensions daily.