Native Wealth-Lab methods have two useful features compared with extension methods. First, they are listed as a drop down which makes them easy to find. Second, when they are selected, they show a helpful, in line, message about what the method is expecting, ie. Bars.Add(). I assume there is no easy way to do this for extensions, such as those found in Community Components, or you would have already done that. If there is a way to do it, I'd be interested in knowing how.

Specifically, I wrote a method for EMA.Value (which the way I use it saves a lot of memory over EMA.Series), and I would like to have this act like a native Wealth-Lab method.

IntelliSense for extensions (addins)

fwiw,
EMA.Value isn't available natively, on purpose. Since the EMA calculation is one of those infinite impulse response series (i.e., unstable indicator), its values stabilize over a [long] period of time, the longer the better. As a rule of thumb we consider IIR-type indicators 'stable' when at least 3 times the period has passed through the calculation. In other words, when using the Series calculation for a 10-bar EMA, you shouldn't use the data until at least bar 30. Otherwise, you risk that the EMA value will be significantly different when a larger (or smaller) amount of seed data are applied.

Of course, if you always use the "Value" method and never the 'Series', the data won't change and will be stable since earlier values aren't used. No problem with that if you like the results. It's just that those EMA values will not come close to match the IIR (correct) value for a given period that includes seed data. I hope I explained this clearly enough.