  One of the strongest absorption lines observed in far-ultraviolet FUSE
spectra of many PG1159 stars remained unidentified up to now. We show that this
line, located at 973.3A, stems from NeVII. We also present new optical
high-resolution spectra of PG1159 stars, obtained with the ESO VLT, which cover
the NeVII 3644A line and a newly identified NeVII multiplet in the 3850-3910A
region. We compare the observed neon lines with NLTE models and conclude a
substantial neon overabundance in a number of objects. Although a detailed
analysis is still to be performed in order to compare quantitatively the
abundances with evolutionary theory predictions, this corroborates the idea
that the PG1159 stars and their immediate progenitors, the [WC]-type nuclei of
planetary nebulae, display intershell matter of their precursor AGB stars.
Possibly as the consequence of a late He-shell flash, H-deficient and
(s-processed) Fe-depleted matter, that is strongly enriched by
3-alpha-processed elements (C, O, Ne), is dredged up to the surface. Hence, a
detailed study of the element abundance patterns in these peculiar stars gives
the unique possibility to probe mixing and nucleosynthesis processes in the
precursor AGB stars.
