FRANKFURT/MUNICH (Reuters) - Siemens (>> Siemens AG) named company insider Ralf Thomas as its new finance chief on Wednesday, replacing Joe Kaeser who was promoted to the chief executive's post last month following the departure of Peter Loescher in a bitter boardroom battle.

Kaeser and his new CFO now face the challenge of whipping into shape the lumbering German engineering conglomerate with 78 billion euros ($104 billion) of annual sales and products ranging from gas turbines to high-speed trains and ultrasound machines.

Siemens shares were up nearly 1 percent at 89.42 euros by 1226 GMT, putting them among the top gainers on Germany's DAX index <.GDAXI>, which was up 0.4 percent.

"With Ralf Thomas, we are gaining an experienced CFO who is very familiar with the circumstances at Siemens through his many years of working at the company," Chairman Gerhard Cromme said in a statement.

Years of breakneck expansion and forays into new businesses, including an ill-fated detour into solar energy which led to a billion-euro loss, have left Siemens in disarray and lagging rivals such as General Electric (>> General Electric Company) in terms of profitability.

Following the ousting of Loescher, who became the first CEO to be hired from outside the company, only to be dismissed after six years in the job following two profit warnings this year, Kaeser indicated a return to the roots of the 166-year-old company. He also renounced the Austrian Loescher's ambitious profit margin target of 12 percent.

He is expected to lay out a more detailed outlook for the company and its 400,000 employees, a third of whom are in Germany, this autumn.

New CFO Thomas, 52, has been finance chief of Siemens' industrial products business for five years, overseeing a series of successful acquisitions of industrial software companies, and takes over as group CFO immediately.

The company also announced on Wednesday that 47-year-old Jim Hagemann Snabe, who is leaving business software maker SAP (>> SAP AG) as co-chief executive, is to join Siemens' supervisory board.

He takes the seat vacated by former Deutsche Bank (>> Deutsche Bank AG) chief executive Josef Ackermann, who resigned earlier this month after a tussle with fellow board members over Loescher's dismissal.

MANAGEMENT TURMOIL

Despite Kaeser's vow to put Siemens back on an "even keel", management has remained in turmoil since Loescher's departure.

Ackermann - who also recently resigned as the chairman of Zurich Insurance (>> Zurich Insurance Group Ltd) following the suicide of the CFO there - is leaving Siemens because he sees "discrepancies in matters of style and fairness", a person familiar with the matter told Reuters, citing a written statement Ackermann made to the supervisory board.

In contrast to Ackermann, one of Europe's most powerful executives, Denmark-born Snabe is known as a soft-spoken intellectual who brings to Siemens an expertise in the software field, having spent more than 20 years at SAP.

Siemens also said on Wednesday that former Bayer (>> Bayer AG) chief executive Werner Wenning, who is already on the supervisory board, takes over Ackermann's role as Cromme's second deputy chairman. German media has speculated in the past that Wenning could have his eye on Cromme's job.

There were also further changes made to the management board on Wednesday, with Brigitte Ederer, 57, who oversees personnel issues, resigning from her post by mutual agreement.

A person familiar with the matter said her departure was due to the Austrian manager's poor relationship with labour representatives at the German engineering group.

Powerful German labour union IG Metall, which is represented on Siemens' supervisory board, put pressure on the board's Chairman Gerhard Cromme to dismiss Ederer, the person said.

Board member Klaus Helmrich, 55, will take over Ederer's duties from October, in addition to his position as chief technology officer.

The reshuffle will leave Siemens with a slimmed down, all-male management board as procurement chief Barbara Kux is already set to leave later this year.

($1=0.7491 euros)

(Additional reporting by Philipp Halstrick; Editing by Greg Mahlich)

By Maria Sheahan and Jens Hack