In order to get all the individual textures for your add-on planes, you will manually have to go in and manually change the ui_tags in the .cfg file.
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This original entry starts out like this...
[fltsim.4]
title=Piper PA22 Tripacer Amphibian Cargo Weathered
sim=pa22
model=c
panel=black
sound=
texture=c
prop_anim_ratio=0.31
kb_checklists=pa22_check
kb_reference=
visual_damage=1
atc_id=N774LB
atc_id_enable=1
atc_id_color=
editable=1
ui_manufacturer=Bill Lyons
ui_type=Piper
ui_variation=PA22 Tripacer Amphibian Cargo Weathered
description=\nThe Tri-Pacer is a remarkable aircraft with performance that...
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will need to end up looking something like this:
[fltsim.4]
title=Piper PA22 Tripacer Amphibian Cargo Weathered
sim=pa22
model=c
panel=black
sound=
texture=c
prop_anim_ratio=0.31
kb_checklists=pa22_check
kb_reference=
visual_damage=1
atc_id=N774LB
atc_id_enable=1
atc_id_color=
editable=1
ui_manufacturer=Piper
ui_type=PA22 Tripacer Amphibian Cargo Weathered
ui_createdby=Bill Lyons
ui_typerole="Single Engine Float Plane"
description=\nThe Tri-Pacer is a remarkable aircraft with performance that...
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Note the elimination of the
ui_variation=
tag and the creation of the
ui_createdby=Bill Lyons
ui_typerole="Single Engine Float Plane"
If you do not do this, you will only get the first variation of the plane in the package.