Setting MAX_SNAPSHOTS on the resource should allow deleting old snapshots.
However this does not work and produces the following error whenever the trigger is executed:
Dec 16 10:14:46 extility jade: Caused by: com.naef.jnlua.LuaRuntimeException: [string "FDL (41c1afa1-863c-3f1f-9f1a-6717b3cb63bc)"]:27: attempt to compare number with string
Using "tonumber()" resolves this error but it produces the same one on line 57. Converting maxSnapshots using "tonumber()" again resolves that issue but it produces yet another error:
Dec 16 10:27:59 extility jade: Caused by: com.naef.jnlua.LuaRuntimeException: [string "FDL (41c1afa1-863c-3f1f-9f1a-6717b3cb63bc)"]:86: attempt to get length of global 'list' (a nil value)