The 68-year-old Steward, who worked with several world champions at his fabled Kronk Gym in Detroit and joined forces with Klitschko in 2004, died on October 25 after developing complications following surgery for diverticulitis.
"It is a big blow to everyone," said the Ukrainian. "It felt strange in preparation ... but we know what he would do and what he would want us to do.
"It is a fight without Emanuel Steward but I will be going into the ring on Saturday with his presence to defend those titles we gathered together."
Vladimir, the younger of the Klitschko brothers who holds the WBO, IBF, IBO and WBA belts, defeated American Tony Thompson in July to retain his titles. Brother Vitali holds the WBC crown.
Vladimir worked with Steward until his hospitalisation in July.
The 36-year-old, who has a record of 58 wins and three defeats, will face a taller opponent for the first time as the 6'6" Wach has one and a half inches on him.
Wach, 32, has a perfect record, with 27 victories from 27 fights, and Klitschko said he would be an agile opponent.
"He is skilled, he can go the distance, there is no doubt about that. For his height he moves very well," explained the champion.
"But I will say one line that Emanuel used to say," said Klitschko as he turned to the Pole sitting near him before adding: "Welcome to big-time boxing."
Wach, dressed in a black shirt and grey suit, looked unfazed and thanked the Ukrainian for giving him a shot at his titles.
"On Saturday you will see a different Mariusz Wach, a Mariusz Wach who will want to take those belts off Klitschko," said the softly-spoken challenger. "You will remember that fight not for hours later but for days and months to come.
"If I need 12 rounds then 12 rounds it is. I am prepared for everything."
- Sports & Recreation
- Emanuel Steward
- Mariusz Wach