No imposition, I enjoy this kind of stuff...and have way to much free time....
Here is the corrected xml text for all 9 power pole objects. Just replace the existing text. Copy and paste the whole block of text, including the leading spaces, as without them Rwy12 might have trouble parsing. I verified that all 9 objects display in the sim.
<obj name="Power Lines, 3 Wires, 1 Pole"
guid="6a45aab4440cda1df1c5d9909456161d"
image="Lars_ExtraObjects\power_3_1_lines.bmp" />
<obj name="Power Lines, 3 Connectors, 1 Pole"
guid="0992da2a42705f451fdb5e86b05cbe6c"
image="Lars_ExtraObjects\power_3_1_nolines.bmp" />
<obj name="Power Lines, 3 Wires, 2 Poles"
guid="345e94f243e20c8300d60e9e2ff03d71"
image="Lars_ExtraObjects\power_3_2_lines.bmp" />
<obj name="Power Lines, 4 Wires, 1 Pole"
guid="8c3f11c54617ed670c23b0a365602e55"
image="Lars_ExtraObjects\power_4_1_lines.bmp" />
<obj name="Power Lines, 4 Connectors, 1 Pole"
guid="789bae8042f4a7a7b706d4a1d1702438"
image="Lars_ExtraObjects\power_4_1_nolines.bmp" />
<obj name="Power Lines, 4 Wires, 2 Poles"
guid="ebccfcfd466e3dd56ccd74b5716a8b75"
image="Lars_ExtraObjects\power_4_2_lines.bmp" />
<obj name="Power Lines, 8 Wires, 1 Pole"
guid="8613afed47cbacfc56663fb7a52798d3"
image="Lars_ExtraObjects\power_8_1_lines.bmp" />
<obj name="Power Lines, 8 Connectors, 1 Pole"
guid="f13896b84b1ba4bcc36e1ab13f391da8"
image="Lars_ExtraObjects\power_8_1_nolines.bmp" />
<obj name="Power Lines, 8 Wires, 2 Poles"
guid="811fded2437c2429c2245d829f608087"
image="Lars_ExtraObjects\power_8_2_lines.bmp" />
Just had a hunch based on experience, not expertise.... I have 2 computers running FS sims. I use(d) Rwy12 on the older one, and now Instant Scenery on the new one. I tried placing a pole with Rwy12 and, sure enough, it didn't show. I then tried with Instant Scenery and they worked. So I figured that...........
Rwy12 uses the model GUID from the 'add_<object_library>.xml' file to build the '<object-placement>.xml'.
Instant Scenery, on the other hand, gets and displays the model GUID directly from the '<object_library>.bgl' in the sim. As it displays the 'live view' of the object I could associate each object with it's model GUID, and compare it to the GUID being used by Rwy12.
When the numbers didn't match I just replaced the GUID's with the correct ones.
A program you might be interested in is
LOM (Library Object Manager) by Jon (Scruffyduck) Masterson. It lets you manage and create new object libraries in several formats, including Rwy12. It, along with his Library Object Viewer, will allow you the associate any library object with its model GUID.
Dave