Any qualified returning veteran shall be eligible to establish creditable service with his or her retirement system or fund for not more than five years of qualified service by complying with the provisions of this article; provided, however, that such five-year period shall be extended by any period of mandatory service imposed by the uniformed service recognized by paragraph (4) of subsection (C) of Section 4312 of federal Public Law 103-353, the Uniformed Service Employment and Reemployment Rights Act of 1994.