TOKYO, Sept 7 (Reuters) - Japan"s Softbank Group (9984.T) said on Tuesday it had agreed a strategic partnership with Deutsche Telekom (DTEGn.DE), Germany"s main telecoms company, which will receive 45 million shares of T-Mobile US (TMUS.O) for 240 million of its shares. Deutsch Telekom will receive another 20 million shares of the No.3 U.S. wireless carrier with proceeds from the sale of T-Mobile Netherlands, Softbank said in a statement. The share swap pact will give the Japanese firm access to about 300 million customers, including 95 million who pay for Deutsche Telekom services, it said.