ZURICH, April 3 (Reuters) - The board of SoftwareOne Holding has been backed by proxy adviser Glass Lewis over the Swiss IT service company's dispute with its founding shareholders.

Glass Lewis has recommended shareholders re-elect all the existing members of the company's board, contrary to the wishes of founding shareholders who had previously wanted to sell the company to Bain Capital.

The board members will all come up for re-election at the company's upcoming shareholder meeting due to be held on April 18.

The board rejected the potential offer from Bain last year which valued SoftwareOne at roughly 3 billion Swiss francs ($3.3 billion), saying it undervalued the company and was not in shareholders' interests.

The three founder shareholders, who together hold 29% of the company's stock, responded by demanding an extraordinary general meeting to replace most of the board of directors.

In its report, Glass Lewis recommended shareholders retain the existing board, citing its "reasonably good faith effort to provide valuable transparency and offer a proportionate compromise".

"We identify no substantive effort to establish that the board was clearly closed-minded or unwilling to engage with prospective counterparties, including Bain," Glass Lewis said.

SoftwareOne declined to comment on the Glass Lewis report.

Earlier on Wednesday the shareholders - Daniel von Stockar, B. Curti Holding AG and René Gill - repeated their call to remove the current board, except Stockar.

"The founding shareholders are convinced that SoftwareOne can best develop with a comprehensive reset at board level," they said in a statement.

Earlier this week, SoftwareOne's board said it had received backing from Institutional Shareholder Services (ISS), another proxy adviser, over the company's plan to elect "a proportionate number" of the founding shareholders' nominees to the board.

($1 = 0.9037 Swiss francs) (Reporting by Oliver Hirt and John Revill Editing by Mark Potter)