Modding army flags

[Lysimachos]

Having created a new army list in a campaign mod I'm working on, I tried to select an appropriate flag for it, inserting the Flag.dds and Armyflag:dds files in the DATA/UI/TEXTURES folder where all this item are placed, naming them Armyflag99 and Flag 99, given that this is the SIDEID of the new army.
It worked correctly for the SideIcon file but it had no effect for the flag which, when opening the battle, is lacking.
Anyone has some idea to solve the problem?

P.S.
The stranger thing is that when - in order to solve the problem - I tried to use a SIDEID of another, preexisting army, deleting it and inserting in his place the new one, removing also the original Armyflag and Flag files, the game anyway continued to show the deleted banner, which seems to mean that there is some other folder from where the information is dragged, but I'm not able to find it ...

[Cronos09]

Having created a new army list in a campaign mod I'm working on, I tried to select an appropriate flag for it, inserting the Flag.dds and Armyflag:dds files in the DATA/UI/TEXTURES folder where all this item are placed, naming them Armyflag99 and Flag 99, given that this is the SIDEID of the new army.
It worked correctly for the SideIcon file but it had no effect for the flag which, when opening the battle, is lacking.
Anyone has some idea to solve the problem?
...

It is not quite clear what flags you are talking about - it is better to show on a screenshot. Flags over units on the battlefield? In this case, you need to make UnitIcons99.dds like the same DDS files in this folder.

[Lysimachos]

Thanks a lot, Cronos!
Your advice was sound and the problem is solved now!