Check out page 186 in the user guide for some direction.
http://support.arubanetworks.com/Documentation/tabid/77/DMXModule/512/Default.aspx?EntryId=8868
Supported modems
USB U720 (Novatel/Qualcomm)
l UM175 (Pantech)
l UM150 (Pantech)
l UMW190(Pantech)
l SXC-1080 (Qualcomm)
l Globetrotter ICON 225
l UMG181
l NTT DoCoMo L-05A (LG FOMA L05A)
l NTT DoCoMo L-02A
l ZTE WCDMA Technologies MSM (MF668?)
l Fivespot (ZTE)
l c-motech CNU-600
l ZTE AC2736
l SEC-8089 (EpiValley)
l Nokia CS-10
l NTT DoCoMo L-08C (LG)
l NTT DoCoMo L-02C (LG)
l Novatel MC545
l Huawei E220 for Movistar in Spain
l Huawei E180 for Movistar in Spain
l ZTE-MF820
l Huawei E173s-1
l Sierra 320
l Longcheer WM72
l U600 (3G mode)
USBConnect 881 (Sierra 881U)
l Quicksilver (Globetrotter ICON 322)
l UM100C (UTstarcom)
l Icon 452
l Aircard 250U (Sierra)
l USB 598 (Sierra)
l U300 (Franklin wireless)
l U301 (Franklin wireless)
l USB U760 for Virgin (Novatel)
Sierra USB-306 (HK CLS/1010 (HK))
l Sierra 306/308 (Telstra (Aus))
l Sierra 503 PCIe (Telstra (Aus))
l Sierra 312 (Telstra (Aus))
l Aircard USB 308 (AT&T's Shockwave)
l Compass 597(Sierra) (Sprint)
l U597 (Sierra) (Verizon)
l Tstick C597(Sierra) (Telecom(NZ))
l Ovation U727 (Novatel) (Sprint)
l USB U727 (Novatel) (Verizon)
l USB U760 (Novatel) (Sprint)
l USB U760 (Novatel) (Verizon)
l Novatel MiFi 2200 (Verizon Mifi 2200)
l Huawei E272, E170, E220 (ATT)
l Huawei E169, E180,E220,E272 (Vodafone/SmarTone (HK))
l Huawei E160 (O2(UK))
l Huawei E160 (SFR (France))
l Huawei E220 (NZ and JP)
l Huawei E176G (Telstra (Aus))
l Huawei E1553, E176 (3/HUTCH (Aus))
l Huawei K4505 (Vodafone/SmarTone (HK))
l Huawei K4505 (Vodafone (UK))
l ZTE MF656 (Netcom (norway))
l ZTE MF636 (HK CSL/1010)
l ZTE MF633/MF636 (Telstra (Aus))
l ZTE MF637 (Orange in Israel)
l Huawei E180, E1692,E1762 (Optus (Aus))
l Huawei E1731 (Airtel-3G (India))
l Huawei E3765 (Vodafone (Aus))
Huawei E3765 (T-Mobile (Germany)
l Huawei E1552 (SingTel)
l Huawei E1750 (T-Mobile (Germany))
l UGM 1831 (TMobile)
l Huawei D33HW (EMOBILE(Japan))
l Huawei GD01 (EMOBILE(Japan))
l Huawei EC150 (Reliance NetConnect+ (India))
l KDDI DATA07(Huawei) (KDDI (Japan))
l Huawei E353 (China Unicom)
l Huawei EC167 (China Telecom)
l Huawei E367 (Vodafone (UK))
l Huawei E352s-5 (T-Mobile (Germany))