Automatic type detection on an enum fails, as the symbol_type returned by ADSIGRP_SYM_INFOBYNAMEEX (in adsGetSymbolInfo) is the name of the enum itself (e.g. E_something) instead of the underlying integer type.

Some testing showed that SAdsSymbolEntry.dataType i.e. the adsDataType of symbol matches the underlying type of the enum e.g. ADST_INT16 for INT and ADST_UINT16 for UINT.
I found this explanation why dataType is not used normally

But it could be used in addition to the symbol_type to detect unknown type names.