Are Improvised weapons that count as real weapons still improvised ?

[Bugromkiller]

I am building a character that want to use the equipment trick: Ladder trick from Adventurer Armory 2 for the Guarding Ladder (Combat Expertise, Combat Reflexes): You can hold a ladder in one hand and treat it as a heavy wooden shield with the fragile special feature.

I assume my ladder count as a shield for feats like Shield Slam but does it still count for Improvised weapon feats and traits like Catch off-guard and Surprise Weapon?

[SlimGauge]

Treating your ladder as a heavy wooden shield is an option. So you have to choose: Do I treat this ladder as a heavy wooden shield this turn, or do I treat it as an improvised weapon (club or quarterstaff or whatever the GM decides) this turn.
I don't think you can do both simultaneously.