Hello Innectis, at the moment Innectis (the best server in the Universe) has not updated to 1.4.6 so to downgrade 1.4.5 just follow these simple steps.
1) Download a clean Minecraft 1.4.5 Jar file --->
assets.minecraft.net/1_4_5/minecraft.jar <---
2) Type %appdata% into the start menu
3) Open .minecraft folder
4) Open the bin folder
5) Delete the current Minecraft.jar file
6) Paste in the Minecraft 1.4.5 jar file and rename it to minecraft
7) Done
Cant figure it out? Install/Run Teamviewer and I can do it for you!