Another tree question..this time FSX

I read something on FSDeveloper.com that probably answers this question, but thought to ask in case someone has found a workaround. Whether using Instant Scenery or Whisplacer, adding trees via vegetation in the scenery library permits the choice of only one season per tree. Of course, when running FSX, only the chosen tree displays all year round - this is definitely unacceptable where we have four very distinct seasons! I also looked into TreeX but it appears that it modifies the textures for all default trees only, and is not able to add additional trees.