Maybe try something like this.
If your "Dates" are in say column A, calculate a new column of Text dates (mmm-yy) to use on your x-axis
In This example, you would chart column B on the X-axis and Column C on the Y axis.
<table border="1" cellspacing="0" cellpadding="0" style="font-family:Arial,Arial; font-size:10pt; background-color:#ffffff; padding-left:2pt; padding-right:2pt; "> <colgroup><col style="font-weight:bold; width:30px; " /><col style="width:64px;" /><col style="width:64px;" /><col style="width:64px;" /></colgroup><tr style="background-color:#cacaca; text-align:center; font-weight:bold; font-size:8pt; "><td >*</td><td >A</td><td >B</td><td >C</td></tr><tr style="height:22px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >1</td><td >Date</td><td >Text Date</td><td >Value</td></tr><tr style="height:22px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >2</td><td style="text-align:right; ">7/9/10</td><td style="text-align:right; ">Jul-10</td><td style="text-align:right; ">1</td></tr><tr style="height:22px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >3</td><td style="text-align:right; ">9/9/10</td><td style="text-align:right; ">Sep-10</td><td style="text-align:right; ">2</td></tr><tr style="height:22px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >4</td><td style="text-align:right; ">10/9/10</td><td style="text-align:right; ">Oct-10</td><td style="text-align:right; ">3</td></tr><tr style="height:22px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >5</td><td style="text-align:right; ">12/9/10</td><td style="text-align:right; ">Dec-10</td><td style="text-align:right; ">4</td></tr><tr style="height:22px ;" ><td style="font-size:8pt; background-color:#cacaca; text-align:center; " >6</td><td style="text-align:right; ">1/9/11</td><td style="text-align:right; ">Jan-11</td><td style="text-align:right; ">5</td></tr></table><br /><table style="font-family:Arial; font-size:10pt; border-style: groove ;border-color:#00ff00;background-color:#fffcf9; color:#000000; "><tr><td ><b>Spreadsheet Formulas</b></td></tr><tr><td ><table border = "1" cellspacing="0" cellpadding="2" style="font-family:Arial; font-size:9pt;"><tr style="background-color:#cacaca; font-size:10pt;"><td >Cell</td><td >Formula</td></tr><tr><td >B2</td><td >=TEXT(A2,"mmm-yy")</td></tr><tr><td >B3</td><td >=TEXT(A3,"mmm-yy")</td></tr><tr><td >B4</td><td >=TEXT(A4,"mmm-yy")</td></tr><tr><td >B5</td><td >=TEXT(A5,"mmm-yy")</td></tr><tr><td >B6</td><td >=TEXT(A6,"mmm-yy")</td></tr></table></td></tr></table>