The developer of Trump Tower Tampa said it plans to resume construction in January and expects the building to be finished by summer 2009.

That may not be enough to satisfy The Donald.

Donald Trump, who licensed his name to the development group, said in an interview that he is unsure the developer, SimDag LLC, will finish the project and wants to take it over.

"The difficulty is they have great confidence they can pull it off," Trump said in a telephone interview. "This is always the difficult part in having partners in something you could pull off easily yourself."

Meanwhile, Frank Dagostino, SimDag's chief executive officer, and Bob Lyons, the company's president, said they have no doubt the high-profile downtown project on the Hillsborough River will be built by their company.

"I'm 100 percent confident," Dagostino said.

Work at the riverfront site, at 111 S. Ashley Drive, halted last month after workers found soil instability beneath the building site. SimDag executives said they expected to receive an engineering report Monday detailing what needs to be done to make sure the weight of the massive structure is properly supported.

SimDag paid Trump millions in a licensing agreement for the 52-story luxury high-rise building but has yet to secure financing to build the $235 million residential condo.

The estimated completion date has been pushed back multiple times since the project was announced two years ago. SimDag has parted ways with at least two contractors and has yet to announce a new one.

Early last year, the company passed on $40 million in construction increases to buyers with reservations to purchase units, originally priced at $700,000 to more than $6 million.

Trump told the Tribune in August that he made SimDag executives an offer to buy them out and build the tower himself. He said Friday that the offer stands, but the local development company wants more time to prove it can build it. Trump declined to disclose details of his offer.

"We have had discussions with [Trump], but it's not for public knowledge," Dagostino said. "If he wants to make it public he can, but we're under confidentiality agreements with him not to discuss our deal.

"I know he's disappointed with the [delay], but we can't control that," Dagostino added. " He's not involved in our day-to-day process and isn't aware of what we're going through."

Lyons said the engineering report will detail how much deeper the steel and concrete pilings will need to be to support the structure.

The new work, coupled with labor, rising construction costs and delays, have added about $5 million to the cost and pushed back the estimated completion date to summer 2009, Lyons said.

The soil testing is part of what has held up financing, the executives said. With the tests back, they expect to have a construction loan soon. They did not disclose details of the report.

Lenders are more reluctant to fund condominium construction in the slowing real estate market, but lenders are bidding to be part of such a large project, they said.

To raise additional cash, SimDag recently sold the CapTrust Building at 102 W. Whiting St. - its downtown headquarters - to a business partner for $6 million. The building is next door to the Trump project site.

Dagostino described the sale as a "refinancing deal." The building was under the same loan as two other parcels, including the Trump site.

"We needed to separate the building from the Trump site," Dagostino said, noting that the purchase agreement gives SimDag five years to buy it back for the same price.

Reporter Shannon Behnken can be reached at (813) 259-7804.