Changing Dimension Values in CALCode (2013).

First Post, apologies if in wrong area.
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I believe I understand the logic of the new dimension structures and the dimensionSetId, but am confused by how to do simple coding with it.

e.g., setting Dim3 of a Customer.
Previously when the data was stored on Table 352 Default Dimension it would have been something like

If r352.get(18,rCustNo,GLSetup."Shortcut Dimension 3 Code") then
begin //found, modify
   validate(r352."Dimension Value Code", 'icarus');
   r352.modify
end
else
begin //not found, insert
   r353.init;
   r352.TableId = 18;
   r352.No. := CustNo;
   r352."Dimension Code" := GLSetup."Shortcut Dimension 3 Code";
   validate(r352."Dimension Value Code", 'icarus');
   r352.insert;
end;

So how would the above code look under the new dimensions. I suspect it is probably really obvious but I can't figure out how its done.
Wayne.